Posts Tagged ‘number’

Increase tomcat MaxThreads values to resolve Tomcat timeout issues and sort

Friday, December 11th, 2015

Increase_Tomcat_MaxThreads_values_to_resolve_Tomcat_timeout-issues-and-sort

Thanks God, we have just completed (6 months) Migration few Tomcat and TomEE application servers for PG / PP and Scorpion instances from old environment to a new one for a customer.

Though the separate instances of the old environment are being migrated, the overall design of the Current Mode of Operations (CMO) as they use to call it in corporate World and the Future Mode of Operations (FMO) has differences.

The each of applications on old environment is configured to run in Tomcat failover cluster (2 tomcats on 2 separate machines with unique IP addresses are running) and Apache Reverse Proxy is being used with BalanceMember apache directive in order to drop requests to Tomcat cluster to Tomcat node1 and node2. On the new environment however by design the Tomcat cluster is removed and the application request has to be served by single Tomcat instance.

The migration completed fine and in the beginning in the first day (day 1) and day 2 since the environment went in Production and went through the so-called "GoLive", as called in Corporate World- which is a meathor for launching the application to be used as a production environment for customer, the customer reported TimeOut issues.

Some of the requests according to their report would took up to 4 minutes to serve, after a bit of investigation we found out, that though the environment was moved to one Tomcat the (number) amount of connections to application of end clients did not change, thus the timeouts were caused by default MaxThreads being reached and, we needed to to obviously raise that number. Here is the old Apache RP config where we had the 2 Tomcats between which the RP was load balancing:
 

BalancerMember ajp://10.10.10.5:11010 route=node1 connectiontimeout=10 ttl=60 retry=60
BalancerMember ajp://10.10.10.5:11010 route=node2 connectiontimeout=10 ttl=60 retry=60

ProxyPass / balancer://pool/ stickysession=JSESSIONID
ProxyPassReverse / balancer://pool/


As we needed a work around, we come to conclusion that we just need to increase Timeout on RP first so on Apache Reverse Proxy we placed following httpd.conf Virtualhost ProxyPass (directive) configs :

 

ProxyPass / ajp://10.10.10.5:11010/ keepalive=On timeout=30 connectiontimeout=30 retry=20
ProxyPassReverse / ajp://10.10.10.5:11010/

ProxyPass / ajp://10.10.10.5:11010/ keepalive=On timeout=30 connectiontimeout=30 retry=20
ProxyPassReverse / ajp://10.10.10.5:11010/


and following Apache Timeout directives options:

 

Timeout 300
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 15


Even though the developer tried to insist that the problem was in Reverse Proxy timeout config, they were wrong as I checked the RP logs and there was no "maximum connections reached" errors..

As you could guess what left to check was only Tomcat, after quick evaluation of server.xml, it turned out that the MaxThreads directive on old clustered Tomcats was omitted at all, meaning the default MaxThreads Tomcat value of 200 maximum connections were used, however this was not enough as the client was quering the application with about 350 connections / sec.

The solution was of course to raise the Maxthreads to 400 we were pretty lucky that we already had a good dedicated Linux machine where the application was hosted (16GB Ram, 2 CPUs x 2.67 Ghz), thus raising MaxThreads to 400 was not such a big deal.

Here is the final config we used to fix tomcat timeouts:
 

<Connector port="11010" address="10.10.10.80" protocol="AJP/1.3" redirectPort="8443" MaxThreads="400" connectionTimeout="300000" keepAliveTimeout="300000" debug="9" />


One note to make here is the debug="9" options to Connector directive was used to increase debug loglevel of Tomcat, and address="" is the local network IP on which Tomcat instance runs. As you see, we choose to use very high connectionTimeouts (because it is crucial, not to cut requests to applications due to timeouts) in case of application slowness.

We also suspected that there are some Oracle (ORA) database queries slowly served on the SQL backend, that might in future cause more app slowness, but this has to be checked seperately further in time as presently we were checking we did not have our Db person present.

 

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Microsoft Windows most secure OS for 2014 ? – Short OS and Application Security report for 2014

Tuesday, February 24th, 2015

windows-more-secure-OS-for-2014-than-Linux-and-Mac-OSX-and-iOS-operating-systems-short-security-report-2014

It is shocking news for me and probably to many that according to security specialists at National Vulnerability Database, at present moment for year 2014 Windows looks like more secure than both Apple's (iOS and Mac OS X) as well as to Linux.

Windows has been  bullied for its bad OS design and easier to breach Security compared to Linux, there was a constant hype also of Mac OS users claiming the invulnerability of their BSD based OS, but it seems security breach statistics given by  National Vulnerability Database security breach evaluation reports tell us security issues for 2014 Windows OSes while compared to other OS vulnerabilities in different operating systems such as Linux.

statistics-of-Operating-System-security-issues-vulnerabilities-for-2014-windows-most-secure-OS-2014-source-national-vulnerability-database
I will have to disappoint Apple Mac fans but in 2014 Mac OS X was found to be riddled with the greatest number of security problems147 in total, including 64 rated as high severity, and 67 as medium.

iOS's security was also ranked poor with 127 vulnerabilities including 32 high and 72 with a medium rating.

For comparison the latest Windows 8.1 had only 36 vulnerabilities, and its predecessors — Windows 8 and 7 — both had same number.
In Enterprise World (users) Windows Server 2007 and 2008 both have 38 vulnerabilities. Reported vulnerabilities were mainly of middle and high severity.

high-severity-vulnerabilities-graph-of-operating-systems-year-2014

Overall statistics also show there has been a huge increase in the number security vulnerabilities in the NVD security reports database.
In 2013 the number of all logged vulnerabilities were 4,794 while this jumped to 7,038 in y. 2014. The good news is lower percentage of all logged in security issues were rated of critical security importance.
It is mostly third party software not part of OS which contain security issues, 83% of all reported vulnerabilities were laying in 3rd party applications, only 13% percantage were OS specific and 4% hardware related.
Though overall statistics shows Microsoft products more secure than Apple Inc. Products and (Open Source) Linux, though still M$ Internet Explorer is the most insecure web browser, for 2014,  Internet Explorer had  242 vulnerabilities while Google Chrome had 124 security issues and the most secure browser rated for 2014 is (surprising for me) Mozilla Firefox.
It is important to say such statistics are not completely relevant because, for example you can rarely see a Linux desktop user infected with Malware but almost everyone around using Windows OS is malware infected, same goes for Mac OS users, there are plenty of vulnerabilities for Mac but overall security of Mac OS is better as I haven't still met Mac OS users with Viruses and Spyware but I fixed about (30!!) of Microsoft PCs and notebooks infected with various Viruses and badware throughout 2014. Also it should be considered that many securitty bugs are kept secret and actively exploited for a long time by blackhats like it happened recently with Heartbleed and ShellShock vulnerabilities
For those interested, below is a list of top vulnerable applications for 2014

security-issues-vulnerability-report-2012-2013-2014_graph_windows-most-secure-operating-system-for-2014

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Joomla 1.5 fix news css problem partial text (article text not completely showing in Joomla – Category Blog Layout problem)

Monday, October 20th, 2014

joomla-fix-weird-news-blog-article-text-incompletely-shown-category-blog-website-layout-problem

I’m still administrating some old archaic Joomla website built on top of Joomla 1.5. Recently there were some security issues with the website so I first tried using jupgrade (Upgrade Joomla 1.5 to Joomla 2.5) plugin to try to resolve the issues. As there were issues with the upgrade, because of used template was not available for Joomla 2.5, I decided to continue using Joomla 1.5 and applied the Joomla 1.5 Security Patch. I also had to disable a couple of unused joomla components and the contact form in order to prevent spammers of randomly spamming through the joomla … the Joomla Security Scanner was mostly useful in order to fix the Joomla security holes ..

So far so good this Joomla solved security but just recently I was asked to add a new article the Joomla News section – (the news section is configure to serve as a mini site blog as there are only few articles added every few months). For my surprise all of a sudden the new joomla article text started displaying text and pictures partially. The weirdly looking newly added news looked very much like some kind of template or css problem. I tried debugging the html code but unfortunately my knowledge in CSS is not so much, so as a next step I tried to temper some settings from Joomla Administrator in hope that this would resolve the text which was appearing from article used to be cut even though the text I’ve placed in artcle seemed correctly formatted. I finally pissed off trying to solve the news section layout problem so looked online too see if anyone else didn’t stick out to same error and I stumbled on Joomla’s forum explaining the Category Blog Layout Problem

The solution to the Joomla incomplete text showing in article is – To go to Joomla administrator menus:

1. Menus -> Main Menu -> (Click on Menu Item(s) – Edit Menu Item(s)) button
2. Click on News (section)
In Parameters section (on the botton right) of screen you will see #Leading set to some low number for example it will be something like 8 or 9. The whole issue in my case was that I was trying to add more than 8 articles and I had a Leading set to 8 and in order to add more articles and keep proper leading I had to raise it to more. To prevent recent leading errors, I’ve raised the Leading to 100 like shown in below screenshot
joomla-blog-layout-basic-parameters-screenshot-fix-joomla-news-cut-text-problem-screenshot

After raising to some high number click Apply and you’re done your problem is solved 🙂
For those curious what the above settings from screenshot mean:

# Leading Articles -> This refers to the number of articles that are to be shown to the full width
# Intro Articles -> This refers to the number of articles that are not to be shown to full width
# Columns -> This refers to the number of columns in which the articles will be shown that are identified as #Intro. If #Intro is zero this setting has no effect
# Links -> Number of articles that are to be shown as links. The number of articles should exceed #leading + #Intro

N.B. Solving this issue took me quite a long time and it caused me a lot of attempts to resolve it. I tried creating the article from scratch, making copy from an old article etc. I even messed few of the news articles one time so badly that I had to recreate them from scratch, before doing any changes to obsolete joomlas always make database and file content backup otherwise you will end up like me in situation loosing 10 hours of your time ..

The bitter experiences once again with Joomla convinced me when I have time I have to migrate this Joomla CMS to WordPress. My so far experience with Joomla prooved to me just for one time the time and nerves spend to learn joomla and built a multi-lingual website with it as well as to administer it with joomla obscure and hard to cryptic interfaces and multiple security issues., makes this CMS completely unworthy to study or use, its hardness to upgrade from release to release, besides its much slow and its less plugins if compared to WordPress makes wordpress much better (and easier to build use platform than Joomla).
So if you happen to be in doubt where to use Joomla or a WordPress to build a new company / community website or a blog my humbe advise is – choose WordPress!

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Merge (convert) multiple PDF files into one single PDF – Generate one pdf from many on Linux / Windows and Mac

Wednesday, August 6th, 2014

merge-convert-many-pdf-files-to-single-one-generate-one-pdf-from-many-pdf-files-linux-windows-mac-pdftk-logo
I was looking for English Orthodox Bible translation of the Old Testament (Septuagint Version) and found such divided in many pdf files. I wanted to create a common (single) PDF from all the separate Old Testamental Book files in order to put it online as it might be convenient for English native speakers to download and later read offline on their computers the Old Testament Orthodox version Holy Bible.

Before I explain how I did it I will make a short turn to explain few things about Septuagint, as this is probably interesting stuff, you might not know.

Septuagint (also referred as LXX or the Alexandrian Canon) – Is Translation of the Hebrew Bible and some related text in Koine Greek) by legendary 70 Jewish scholars as early as the 2nd century BC. Just for those interested in Christianity it is curious fact that the number of Old Testament books are different among Protestant, Roman Catholic and Orthodox Christians, whether the number of New Testament books are the same in Catholics, Protestant and Orthodox.

So How Many books are in Roman Catholic, Protestant and Orthodox Old Testament Holy Bible?

The Old Testament in Orthodox Holy Bible version has 50 (where Slavonic versions of the bible include also +2 More which are the  Edras books), whether protestant Holy Bible includes only 39 books in old testament and Roman Catholics has 46 old testamental books in there bibles. The reason why Protestants choose to have less books (only 39) is some of the books in the Roman Catholic and Orthodox Church are Apocryphal are referred to as the Apocryphal, or Deuterocanonical books this doesn't mean that the extra 8 Books in Orthodox Bibles are not God Inspired, this means, they don't have the historic authenticity as the early Church accepted canonicals.

The Orthodox Church accepted the Septuagint LXX as divinely inspired to be used in Church.

Now back to how I managed to merge (convert) multiple PDF files into single PDF on my Debian Linux home router.

My first attempt was with ImageMagick's convert (in the same manner as I used to generate PDF files from pictures earlier), e.g.:
 

convert intro.pdf genesis.pdf exodus.pdf leviticus.pdf numbers.pdf deuteronomy.pdf … SINGLE-FILE.PDF

I waited for convertion to complete quite long but it seemed looping so finally after 7 minutes I stopped it and decided to try with something else and, after quick search I found pdftk.

pdftk has plenty of functions and is great for anyone who needs to do Merge / Split Update / Encrypt / Repair corrupted PDFs on Linux:

 apt-cache show pdftk |grep -i desc -A 17
Description: tool for manipulating PDF documents
 If PDF is electronic paper, then pdftk is an electronic stapler-remover,
 hole-punch, binder, secret-decoder-ring, and X-Ray-glasses. Pdftk is a
 simple tool for doing everyday things with PDF documents. Keep one in the
 top drawer of your desktop and use it to:
  – Merge PDF documents
  – Split PDF pages into a new document
  – Decrypt input as necessary (password required)
  – Encrypt output as desired
  – Fill PDF Forms with FDF Data and/or Flatten Forms
  – Apply a Background Watermark
  – Report PDF on metrics, including metadata and bookmarks
  – Update PDF Metadata
  – Attach Files to PDF Pages or the PDF Document
  – Unpack PDF Attachments
  – Burst a PDF document into single pages
  – Uncompress and re-compress page streams
  – Repair corrupted PDF (where possible)

To install pdftk on Debian Linux Lenny / Wheezy:

apt-get install –yes pdftk

After installed to convert a number of separate PDF files into single (merged) PDF file:
 

pdftk file1.pdf file2.pdf file3.pdf cat output single-merged-pdf-file.pdf

 

 

pdftk intro.pdf genesis.pdf exodus.pdf leviticus.pdf numbers.pdf deuteronomy.pdf joshua.pdf judges.pdf ruth.pdf kingdoms_1.pdf kingdoms_2.pdf kingdoms_3.pdf kingdoms_4.pdf paraleipomenon_1.pdf paraleipomenon_2.pdf esdras_1.pdf esdras_2.pdf nehemiah.pdf tobit.pdf judith.pdf esther.pdf maccabees_1.pdf maccabees_2.pdf maccabees_3.pdf psalms.pdf job.pdf proverbs_of_solomon.pdf ecclesiastes.pdf song_of_songs.pdf wisdom_of_solomon.pdf wisdom_of_sirach.pdf hosea.pdf amos.pdf micah.pdf joel.pdf obadiah.pdf jonah.pdf nahum.pdf habbakuk.pdf zephaniah.pdf malachi.pdf isaiah.pdf jeremiah.pdf baruch.pdf lamentations_of_jeremiah.pdf an_epistle_of_jeremiah.pdf ezekiel.pdf daniel.pdf maccabees_4.pdf slavonic_appendix.pdf cat output Orthodox-English-translation-of-Old-Testament-Septuagint.pdf

And Hooray! It worked The resulting share Old Testament (Orthodox) English translation from Septuagint PDF is here

pdftk is also ported for Fedora / CentOS / RHEL etc. (RPM distros), so you to install it there:

yum -y install pdftk

Or if missing in repositories grab the respective pdf and

rpm -ivh pdftk-*yourarch.pdf

PDFtk has also Windows and Mac OS version just in case if you need to script Merging of multiple PDFs to single ones for more check out PDftk Server page homepage here

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Make Viber calls with no smartphone from Mobile to PC and from PC to Mobile – Bluestacks install android mobile apps on PC

Thursday, April 24th, 2014

Viber-for-smartphones-connect-freely-through-internet-voip-on-your-mobile

Since I've bought ZTE smat phone and I have Android on it, decided to install   Viber – iOS, Android and Desktop PC – Free Calls, Text and Picture sharing through the internet app. Viber is used by a lot of my people including many friends already so I installed it as well to be possible to speak for free with close friends …

Why Viber?


What makes this nifty app so great is its capability to make free calls over mobile phones through the Internet Viber.
Viber saves you a lot of money as calls are handled only through the Internet (you need Wifi on your mobile or Mobile 3G Internet access on phone) and you don't need to pay to your mobile operator 0.10 – 0.15 euro / cents per minute. Besides being Free another advantage of Viber is conversations sound quality which is much better than a regular phone call

Viber doesn't need a special registration, but as (login) identificator uses your mobile phone number – you just need to have a working Mobile operator phone num. Once registered under a number even if you change your mobile sim card to other operator (for example moving from country to country) still the Viber account will continue work. Another good reason to use Viber is it makes possible price free calls between different countries (for example if you travel a lot and you want to regularly speak with your wife) – in my case right now I'm in Bulgaria and my wife is in Belarus, so to save money and keep talking daily we use Viber daily.

What Devices and Operating System Viber Supports and what is Viber advantages / disadvantages ?


Another reason why Viber is so great is its multi-platform support it works on iPhone, Blackberry, Windows Phone, Nokia (Symbian), Windows, Mac OS and even (Korean own OS-ed) Bada devices. Some might argue that Viber is inferior to Skype and interms of Voice and Video quality its better because of its enhanced HD voice enhanced codecs, besides that Viber's video is still in Beta. However Viber has one big advantage it makes easy possible to reach people using just their Mobile Phone numbers where in Skype it takes time and effort to register in Skype install application on your Mobile keep yourself logged in in Skype and have all contacts previously added, all this happens automatically in Viber in time of installation of Viber App on your mobile.
 

Which Is Cheaper Viber or Skype?

Skype_VS_Viber-VOIP-Prices-which-is-cheaper-skype-or-viber


Once installed Viber could integrate itself with rest of your Mobile OS Call Manager and in time of call a friend number you have the opportunity to make it free Viber call. Viber are also selling Viber Credits so if you want to use your Viber Voice Over IP you can call external mobile operator numbers on a very very cheap price. Viber Calls to landline or mobile phones could be up to 400% cheaper than Skype! Whether you own a Smartphone it will be nice to give Viber a try.

Viber – How to make Phone calls between Desktop PC and Smarphone Mobile

 

One not so standard Viber use is to make Viber calls with no smartphone (at hand) from PC to another Viber equipped Mobile and vice versa.
I needed to make Viber calls from my ZTE Android running mobile to my wife's MacBook Air PC because her mobile is an old Nokia running obscure Symbian version which is not supporting Viber + she doesn't have an Internet access tariff switched on her mobile.

Here is what I had to do to make Phone calls between my Mobile Viber App and my wife's MacbookAir Notebook PC:
 

  • Install BlueStacks Web App Player

     

     

     

    BlueStacks_emulate-google-appstore-on-Windows-and-Mac-OS-android-emulator_Logo
    BlueStacks App Player is a software designed to enable Android applications to run on Windows PC, Apple Macintosh Computers and Windows tablets. BlueStacks is something like (VMware, Qemu) Virtual Machine which allows you to install and run any Android App on your Desktop PC.
    Its curious that app was created by Rosen Sharma in 2008 an ex CTO (Chief Technology Officer) of McAfee
     

  •  A mobile phone with a working SIM card (Nokia 6310 or any old mobile no need to be a smartphone
     
  • Desktop PC with Windows 7, 8 or PC with Mac OS


Install Bluestacks

BlueStacks is needed in order to emulate a smartphone on your PC, therefore once setupped Bluestacks. Launch it and  inside its necessary to login with your Gmail (Google Account) in order to allow access to Google Play Appstore on your PC.
viber with no mobile phone bluestacks
 

Installing and Verifying Viber

This is the most crucial and tricky part in order to make Viber working on any device you need to receive a special Viber verification code, you need to fill in this code to confirm Viber installation on PC. Here I assume you have BlueStacks running with Viber Application installed.

viber-running-under-bluestacks-on-windows-7-8-screenshot

First will be prompted to Agree with Terms and Conditions and provide Mobile Phone number for verification. Tell the Viber app that you have a smartphone with Viber already when prompted. After receving Viber Verification Code you need to fill in this code into BlueStacks Window (inside Viber should be running), go further to next step and you should be done with Desktop PC Viber number registration.

N.B. ! One brackets to open here is you need to have a working Mobile Phone number where you will receive the verification code as SMS, otherwise you cannot get the verification. On your filled in mobile phone number you will get the verification code as SMS.

Making Viber Calls to (Windows Mac) PC without Smartphone

There is no more further need for BlueStacks so you can uninstall it, however I preferred to keep it as its useful to be able to install Android Applications straight on your Desktop PC. To start using Viber on Desktop, just launch Viber application (not through BlueStacks) but the direct install.

Use Viber dial pad to dial your desired remote Smartphone number with Viber equipped.
Enjoy the free Internet calls ! 🙂
 

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Best Windows tools to Test (Benchmark) Hard Drives, SSD Drives and RAID Storage Controllers

Wednesday, April 23rd, 2014

atto-windows-hard-disk-benchmark-freeware-tool-screenshot-check-hard-disk-speed-windows
Disk Benchmarking is very useful for people involved in Graphic Design, 3D modelling, system admins  and anyone willing to squeeze maximum of his PC hardware.

If you want to do some benchmarking on newly built Windows server targetting Hard Disk performance, just bought a new hard SSD (Solid State Drives) and you want to test how well Hard Drive I/O operations behave or you want to see a regular HDD benchmarking of group of MS Windows PCs and plan hardware optiomization, check out ATTO Disk Benchmark.

So why exactly ATTO Benchmark? – Cause it is one of the best Windows Free Benchmark tools on the internet.

ATTO is a widely-accepted Disk Benchmark freeware utility to help measure storage system performance. ATTO though being freeware is among top tools utilized in industry. It is very useful in comparing different Hard Disk vendors speed, measure Windows storage systems performance with various transfer sizes and test lengths for reads and writes.

ATTO Disk Benchmark is used by manufacturers of Hardware RAID controllers, its precious tool to test Windows storage controllers, host bus adapters (HBAs).

Here is ATTO Benchmark tool specifications (quote from their webstie):
 

  • Transfer sizes from 512KB to 8MB
  • Transfer lengths from 64KB to 2GB
  • Support for overlapped I/O
  • Supports a variety of queue depths
  • I/O comparisons with various test patterns
  • Timed mode allows continuous testing
  • Non-destructive performance measurement on formatted drives
  • Transfer sizes from 512KB to 8MB
  • Transfer lengths from 64KB to 2GB
  • Support for overlapped I/O
  • Supports a variety of queue depths
  • I/O comparisons with various test patterns
  • Timed mode allows continuous testing
  • Non-destructive performance measurement on formatted drives
  • – See more at: http://www.attotech.com/disk-benchmark/#sthash.rRlgSTOE.dpuf

Here is mirrored latest version of ATTO Disk for Download. Once you get your HDD statistics you will probably want to compare to other people results. On  TomsHardware's world famous Hardware geek site there are plenty of Hard Drives performance Charts

Of course there are other GUI alternatives to ATTO Benchmark one historically famous is NBench

NBench

nbench_benchmark_windows_hard-drive-cpu-and-memory

Nbench is nice little benchmarking program for Windows NT. Nbench reports the following components of performance:

CPU speed: integer and floating operations/sec
L1 and L2 cache speeds: MB/sec
main memory speed: MB/sec
disk read and write speeds: MB/sec

SMP systems and multi-tasking OS efficiency can be tested using up to 20 separate threads of execution.

For Console Geeks or Windows server admins there are also some ports of famous *NIX Hard Disk Benchmarking tools:

NTiogen

NTiogen benchmark was written by Symbios Logic, It's Windows NT port of their popular UNIX benchmark IOGEN. NTIOGEN is the parent processes that spawns the specified number of IOGEN processes that actually do the I/O.
The program will display as output the number of processes, the average response time, the number of I/O operations per second, and the number of KBytes per second. You can download mirror copy of Ntiogen here


There are plenty of other GUI and Console HDD Benchmarking Win Tools, i.e.:

IOMeter (ex-developed by Intel and now abandoned available as open source available on SourceForge)

iometer-benchmark-disk-storage-speed-windows
 

Bench32 – Comprehensive benchmark that measures overall system performance under Windows NT or Windows 95, now obsolete not developed anymore abandoned by producer company.

ThreadMark32 – capable of bench (ex developed and supported by ADAPTEC) but also already unsupported

IOZone – filesystem benchmark tool. The benchmark generates and measures a variety of file operations. Iozone has been ported to many machines and runs under many operating systems.
 

N! B! Important note to make here is above suggested tools will provide you more realistic results than the proprietary vendor tools shipped by your hardware vendor. Using proprietary software produced by a single vendor makes it impossible to analyze and compare different hardwares, above HDD benchmarking tools are for "open systems", e.g. nomatter what the hardware producer is produced results can be checked against each other.
Another thing to consider is even though if you use any of above tools to test and compare two storage devices still results will be partially imaginary, its always best to conduct tests in Real Working Application Environments. If you're planning to launch a new services structure always test it first and don't rely on preliminary returned soft benchmarks.

if you know some other useful benchmarking software i'm missing please share.

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Saint Cyprian the Bulgarian – Metropolitan of Moscow and All Russians

Thursday, March 13th, 2014

Saint Cyprian the Bulgarian Metropolitan of Moscow and All Russians

Probably few Bulgarians and even less Russians have heard about Saint Cyprian the Bulgariana great saint who played a ey role in esblishment of nowadays Russian Orthodox Church.. I have learned about the living of the saint just recently. Cyprian (The Bulgarian) (c. 1336 – 16 September 1406) was Metropolitan of Kiev and All Rus' with the Metropolitan's residence in Moscow. (The official title was Metropolitan of Kiev and All Rus' until 1448, even though the metropolitans were in Vladimir-on-Kliazma and later Moscow since 1299.)

Saint Cyprian was a Clergyman of Bulgarian nationality, he lived for some time at Mount Athos. In 1373, the Patriarch of Constantinople Philotheus Kokkinos picked him for his devout lifestyle and excellent education and sent him to Lithuania and Muscovy on a mission to reconcile the princes of Lithuania and Tver with Metropolitan Alexius. In 1375, after the hostilities between Moscow and Lithuania had started all over again, the Lithuanian princes asked to appoint Cyprian their Metropolitan. Philotheus Kokkinos made Cyprian Metropolitan of Kiev, all Russia and Lithuania, so that he could unite both ecclesiastical provinces after the death of Alexius. In 1376 he was ordained as a bishop in Constantinople at the behest of the Lithuanian grand duke Algirdas and become Mitropolitan of Kiev. Because this ordination was not recognized by Moscow, he was driven out from Moscow on his first arival there and had to wait in Constantinople until he was officially recognized as Metropolitan. He became officially regognized metropolitan of "all Rus" by the Moscow Duke later in 1389.

His residence from there on was Moscow, although he visited Kiev and other Ukrainian eparchies regularly. In 1378, Metropolitan Alexius died. As a result of the ensuing skirmishes and intrigues, Cyprian became Metropolitan of Moscow in 1381. One year later, however, he fled from Moscow due to the approaching armies of Tokhtamysh. Subsequently, he was removed from Russia and replaced with Metropolitan Pimen (1382–1384). The latter was succeeded by Metropolitan Dionysius (1384–1385). In 1390, Cyprian was returned to Moscow by Vasili II, who he had always supported, and appointed Metropolitan of Moscow and All Russia. Cyprian is remembered as a wise and experienced church administrator who fought for the unity of the Russian church.

In fact, he is mainly responsible for uniting the Church in Russia and the Grand Duchy of Lithuania. He faced serious opposition during his metropolitanate; Dmitry Donskoy and his advisors were excommunicated for opposing Cyprian's efforts to take up his place in Moscow, and Novgorod the Great – especially Archbishops Aleksei and Ioann II – also opposed his efforts to adjudicate ecclesiastical cases there, which would have allowed him to gain the court fees from Novgorod during the time he sat in judgement there. St. Cyprian was an erudite person and oversaw the copying and creation of a number of important works, including the Troitskaia Chronicle (or Troitskaya letopis') and, probably, the Metropolitan Justice (also known as the Pravosudiye metropolich’ye or Правосудие митрополичье). He also rewrote the Life of Metropolitan Peter, originally written around 1327.

Under st. Cyprian's governance, a church "reform"  was made on how the iconostasis is build the called "high few raws of icons" on the Church Alter wall iconostasis so common nowadays in Russian Church is actually his invention.
He also corrected biblical books and translated a number of ecclesiastic works from Greek into Old Church Slavic.
A little known fact is Andrei Rublev was under St. Cyprian's spiritual guidance when he painted the most famous Russian icon (and the only canonical icon depicing) "The Holy Trinity".

Andrey_Rublev_The_old-testament-Holy_Trinity_icon made under spiritual guidance of Saint Cyprian the Bulgarian

St. Cyprian is buried in the Assumption Cathedral in the Moscow Kremlin. He was canonized by the Russian Orthodox Church in the 15th century. One curious fact is St. Kiprian Peak on Greenwich Island in the South Shetland Islands, Antarctica is named for Cyprian.

Here is a movie Saint Cyprian the Bulgarian (unfortunatelyin Bulgarian language)

:

Film about Saint Cyprian the Bulgarian – Metropolitan of Moscow and All Russians

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Preserve Session IDs of Tomcat cluster behind Apache reverse proxy / Sticky sessions with mod_proxy and Tomcat

Wednesday, February 26th, 2014

apache_and_tomcat_merged_logo_prevent_sticky_sessions
Having a combination of Apache webservice Reverse Proxy to redirect invisibly traffic to a number of Tomcat server positioned in a DMZ is a classic task in big companies Corporate world.
Hence if you work for company like IBM or HP sooner or later you will need to configure Apache Webserver cluster with few running Jakarta Tomcat Application servers behind. Scenario with necessity to access a java based application via Tomcat which requires logging (authentication) relaying on establishing and keeping a session ID is probably one of the most common ones and if you do it for first time you will probably end up with Session ID issues.  Session ID issues are hard to capture at first as on first glimpse application will seem to be working but users will have to re-login all the time even though the programmers might have coded for a session to expiry in 30 minutes or so.

… I mean not having configured Session ID prevention to Tomcats will cause random authentication session expiries and users using the Tomcat app will be unable to normally access below application with authenticated credentials. The solution to these is known under term "Sticky sessions"
To configure Sticky sessions you need to already have configured Apache/s with following minimum configuration:

  • enabled mod_proxy, proxy_balancer_module, proxy_http_module and or mod_proxy_ajp (in Apache config)

  LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_http_module modules/mod_proxy_http.so

  • And configured and tested Tomcats running an Application reachable via AJP protocol

Below example assumes there is Reverse Proxy Load Balancer Apache which has to forward all traffic to 2 tomcats. The config can easily be extended for as many as necessary by adding more BalancerMembers.

In Apache webserver (apache2.conf / httpd.conf) you need to have JSESSIONID configured. These JSESSIONID is going to be appended to each client request from Reverse Proxy to each of Tomcat servers with value opened once on authentication to first Tomcat node to each of the other ones.

<Proxy balancer://mycluster>
BalancerMember ajp://10.16.166.53:11010/ route=delivery1
BalancerMember ajp://10.16.166.66:11010/ route=delivery2
</Proxy>

ProxyRequests Off
ProxyPass / balancer://mycluster/ stickysession=JSESSIONID
ProxyPassReverse / balancer://mycluster/

The two variables route=delivery1 and route=delivery2 are routed to hosts identificators that also has to be present in Tomcat server configurations
In Tomcat App server First Node (server.xml)

<Engine name="Catalina" defaultHost="localhost" jvmRoute="delivery1">

In Tomcat App server Second Node (server.xml)

<Engine name="Catalina" defaultHost="localhost" jvmRoute="delivery2">

Once Sticky Sessions are configured it is useful to be able to track they work fine this is possible through logging each of established JESSSIONIDs, to do so add in httpd.conf

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"\"%{JSESSIONID}C\"" combined

After modifications restart Apache and Tomcat to load new configs. In Apache access.log the proof should be the proof that sessions are preserved via JSESSIONID, there should be logs like:
 

127.0.0.1 - - [18/Sep/2013:10:02:02 +0800] "POST /examples/servlets/servlet/RequestParamExample HTTP/1.1" 200 662 "http://localhost/examples/servlets/servlet/RequestParamExample" "Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130807 Firefox/17.0""B80557A1D9B48EC1D73CF8C7482B7D46.server2"

127.0.0.1 - - [18/Sep/2013:10:02:06 +0800] "GET /examples/servlets/servlet/RequestInfoExample HTTP/1.1" 200 693 "http://localhost/examples/servlets/" "Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130807 Firefox/17.0""B80557A1D9B48EC1D73CF8C7482B7D46.server2"

That should solve problems with mysterious session expiries 🙂

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Web Application Load Balancer types and when to use what kind of Load Balancer

Monday, February 3rd, 2014

General load balancer types description / active / passive / static / dynamic and additional
In this small article I will try to clear it up the general types of Web Server Load Balancers available. Whether one choose a Load Balancer he has the option to use a software LB or a hardware LB one there are plenty of software load balancer scripts out there. In this pos t I will mention just what choice is available in hardware load balancer interface BigIP LTM F5 standard. Generally BigIP LTM Load Balancers can be grouped in Static, Dynamic and Additional. One or more Load Balancers can be configured in front of group or farm of appplication servers. When more than one load balancer is used in front of application Load Balancer could be Active Load Balancer and Passive Load Balancer.
Below information will hopefully be useful to Web and Middleware working sys admins and anybody involved in frequent and large web systems integration.

Static Load Balancing

LB_RoundRobin_ type of load balancing example picture


Round Robin
Load Balancing

This is the default load balancing method. Round Robin mode passes each new connection request to the next server in line, eventually distributing connections evenly across the array of machines being load balanced.
Round Robin mode works well in most configurations, especially if the equipment that you are load balancing is roughly equal in processing speed and memory.

ratio_member_load_balancer picture diagram

Ratio (member) / Ratio (node) Load Balancer

   
The Ratio (member) system distributes connections among pool members or nodes in a static rotation according to ratio weights that you define. In this case, the number of connections that each system receives over time is proportionate to the ratio weight you defined for each pool member or node. You set a ratio weight when you create each pool member or node.

These are static load balancing methods, basing distribution on user-specified ratio weights that are proportional to the capacity of the servers.

dynamic_ratio_member_load_balancer picture diagram

Dynamic Load Balancers

 

Dynamic Ratio (member) Dynamic Ratio (node) LB

The Dynamic Ratio load balancing select a server based on various aspects of real-time server performance analysis. These methods are similar to the Ratio methods, except that with Dynamic Ratio methods, the ratio weights are system-generated, and the values of the ratio weights are not static. These methods are based on continuous monitoring of the servers, and the ratio weights are therefore continually changing.
   
The Dynamic Ratio LBs are used specifically for load balancing traffic to RealNetworks® RealSystem® Server platforms, Windows® platforms equipped with Windows Management Instrumentation (WMI), or any server equipped with an SNMP agent such as the UC Davis SNMP agent or Windows 2000 Server SNMP agent.

dynamic_load_balancing load balancer diagram picture with circles

Fastest (node) /Fastest (application) LB

   
The Fastest methods select a server based on the least number of current sessions. The following rules apply to the Fastest load balancing methods:

These LB require that you assign both a Layer 7 and a TCP type of profile to the virtual server interface where LB IP is binded.
If a Layer 7 profile is not configured, the virtual server falls back to Least Connections load balancing mode.

Note: If the OneConnect feature is enabled, the Least Connections methods do not include idle connections in the calculations when selecting a pool member or node. The Least Connections balancing use only active connections in their calculations.
   
Fastest node load balancing is useful in environments where nodes are distributed across separate logical networks.

 

Least Connections (member) / Least Connections (node) LB    

The Least Connections method are relatively simple in that the system passes a new connection to the pool member or node that has the least number of active connections.

Note: If the OneConnect feature is enabled, the Least Connections methods do not include idle connections in the calculations when selecting a pool member or node. The Least Connections methods use only active connections in their calculations.
   
The Least Connections balancing function best in environments where the servers have similar capabilities. Otherwise, some amount of latency can occur.

For example, consider the case where a pool has two servers of differing capacities, A and B. Server A has 95 active connections with a connection limit of 100, while server B has 96 active connections with a much larger connection limit of 500. In this case, the Least Connections method selects server A, the server with the lowest number of active connections, even though the server is close to reaching capacity.

If you have servers with varying capacities, consider using the Weighted Least Connections load balancing instead.

 

Weighted Least Connections (member) / Weighted Least Connections (node)

Like  Least Connections, these load balancing methods select pool members or nodes based on the number of active connections. However, the Weighted Least Connections methods also base their selections on server capacity.

The Weighted Least Connections (member) method specifies that the system uses the value you specify in Connection Limit to establish a proportional algorithm for each pool member. The system bases the load balancing decision on that proportion and the number of current connections to that pool member. Example is member_a has 40 connections and its connection limit is 200, so it is at 20% of capacity. Similarly, member_b has 40 connections and its connection limit is 400, so it is at 10% of capacity. In this case, the system select selects member_b. This algorithm requires all pool members to have a non-zero connection limit specified.

The Weighted Least Connections (node) method specifies that the system uses the value you specify in the node's Connection Limit setting and the number of current connections to a node to establish a proportional algorithm. This algorithm requires all nodes used by pool members to have a non-zero connection limit specified.

If all servers have equal capacity, these load balancing  behave in the same way as the Least Connections methods.

Note: If the OneConnect feature is enabled, the Weighted Least Connections methods do not include idle connections in the calculations when selecting a pool member or node. The Weighted Least Connections  use only active connections in their calculations.
   

Weighted Least Connections methods work best in environments where the servers have differing capacities.
For example, if two servers have the same number of active connections but one server has more capacity than the other, the BIG-IP system calculates the percentage of capacity being used on each server and uses that percentage in its calculations.

 

Observed (member) / Observed (node)

With the Observed methods, nodes are ranked based on the number of connections. The Observed methods track the number of Layer 4 connections to each node over time and creates a ratio for load balancing.
   

The need for the Observered methods is rare, and they are not recommended for large pools.

Predictive (member) / Predictive (node)

The Predictive methods use the ranking methods used by the Observed methods, where servers are rated according to the number of current connections. However, with the Predictive methods, the BIG-IP system analyzes the trend of the ranking over time, determining whether a nodes performance is currently improving or declining. The servers with performance rankings that are currently improving, rather than declining, receive a higher proportion of the connections.
   

The need for the Predictive methods is rare, and they are not recommend for large pools.

Least Sessions LB type

The Least Sessions method selects the server that currently has the least number of entries in the persistence table. Use of this load balancing method requires that the virtual server reference a type of profile that tracks persistence connections, such as the Source Address Affinity or Universal profile type.

Note: The Least Sessions methods are incompatible with cookie persistence.
   
The Least Sessions method works best in environments where the servers or other equipment that you are load balancing have similar capabilities.

 

L3 Address

L3 Address is same LB type as Least Connections methods.
  

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How to disable Debian GNU / Linux (Squeeze) Apache 2 version reporting to improve security – Hide Apache server version

Friday, October 5th, 2012

Debian GNU / Linux's Apache default behavior is to report Apache server name, version and Linux distribution version and codename.
This is shown as a minor security leak in many Security Scanner (audit) software like Nessus. It reveals a vital information which could help malicious attacker later to use exploit if the version number in question is vulnerable.

The quickest way to check, either Apache versioning and distro info is disabled is with telnet:

hipo@noah:~/Desktop$ telnet pc-freak.net 80
Trying 83.228.93.76…
Connected to pc-freak.net.
Escape character is '^]'.
HEAD / HTTP/1.0

Connection closed by foreign host.
hipo@noah:~/Desktop$ telnet pc-freak.net 80
Trying 83.228.93.76…
Connected to pc-freak.net.
Escape character is '^]'.
HEAD / HTTP/1.0

HTTP/1.1 200 OK
Date: Fri, 05 Oct 2012 10:48:36 GMT
Server: Apache/2.2.16 (Debian)
X-Powered-By: PHP/5.3.3-7+squeeze14
Vary: Accept-Encoding
Connection: close
Content-Type: text/html

Disabling this Distro version codename and version number reporting on Debian is done by changing in file /etc/apache2/conf.d/security directives:


ServerTokens OS
ServerSignature On

to


ServerSignature Off
ServerTokens ProductOnly

Here important note to make is if you try adding:

ServerSignature Off and ServerTokens Prod straight in Debian general config /etc/apache2/apache2.conf, but did not change the settings set for the vars through /etc/apache2/conf.d/security; settings from /etc/apache2/conf.d/security will overwrite ServerSignature / ServerTokens settings set in /etc/apache2/apache2.conf

I tried this myself (forgotting about /etc/apache2/conf.d/security) and adding both variables straight in apache2.conf. After Apache restart Apache version number and type of distribution continued be returned by the WebServer.
I thought something specific changed in Debian Squeeze – Apache/2.2.16 so this two variables are probably not working so I did a quick research online seing other people complaining also unable to disable Apache ver and Linux distro version and looking for a reason why. Well anyways if you happen to also ponder, why ServerSignature Off and ServerTokens ProductOnly does not take effect keep in mind it is due to overwritten settings via /etc/apache2/conf.d/security, changing the values there and restarting Apache and you're done 🙂

To make sure 100% Apache is no longer returning exact version number and host installed distro type, use telnet again:

hipo@noah:~/Desktop$ telnet pc-freak.net 80
Trying 83.228.93.76…
Connected to pc-freak.net.
Escape character is '^]'.
HEAD / HTTP/1.0

Connection closed by foreign host.

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