Posts Tagged ‘sysadmin’

How to disable Windows pagefile.sys and hiberfil.sys to temporary or permamently save disk space if space is critically low

Monday, March 28th, 2022

howto-pagefile-hiberfil.sys-remove-reduce-increase-increase-size-windows-logo

Sometimes you have to work with Windows 7 / 8 / 10 PCs  etc. that has a very small partition C:\
drive or othertimes due to whatever the disk got filled up with time and has only few megabytes left
and this totally broke up the windows performance as Windows OS becomes terribly sluggish and even
simple things as opening Internet Browser (Chrome / Firefox / Opera ) or Windows Explorer stones the PC performance.

You might of course try to use something like Spacesniffer tool (a great tool to find lost data space on PC s short description on it is found in my previous article how to
delete temporary Internet Files and Folders to to speed up and free disk space
 ) or use CCleaner to clean up a bit the pc.
Sometimes this is not enough though or it is not possible to do at all the main
partition disk C:\ is anyhow too much low (only 30-50MB are available on HDD) or the Physical or Virtual Machine containing the OS is filled with important data
and you couldn't risk to remove anything including Internet Temporary files, browsing cookies … whatever.

Lets say you are the fate chosen guy as sysadmin to face this uneasy situation and have no easy
way to add disk space from another present free space partition or could not add a new SATA hard drive
SSD drive, what should you do?
 

The solution wipe off pagefile.sys and hiberfil.sys

Usually every Windows installation has a pagefile.sys and hiberfil.sys.

  • pagefile.sys – is the default file that is used as a swap file, immediately once the machine runs out of memory. For Unix / Linux users better understanding pagefile.sys is the equivallent of Linux's swap partition. Of course as the pagefile is in a file and not in separate partition the swapping in Windows is perhaps generally worse than in Linux.
  • hiberfil.sys – is used to store data from the machine on machine Hibernation (for those who use the feature)


Pagefile.sys which depending on the configured RAM memory on the OS could takes up up to 5 – 8 GB, there hanging around doing nothing but just occupying space. Thus a temporary workaround that could free you some space even though it will degrade performance and on servers and production machines this is not a good solution on just user machines, where you temporary need to free space any other important task you can free up space
by seriously reducing the preconfigured default size of pagefile.sys (which usually is 1.5 times the active memory on the OS – hence if you have 4GB you would have a 6Gigabytes of pagefile.sys).

Other possibility especially on laptop and movable devices running Win OS is to disable hiberfil.sys, read below how this is done.


The temporary solution here is to simply free space by either reducing the pagefile.sys or completely disabling it


1. Disable pagefile.sys on Windows XP, Windows 7 / 8 / 10 / 11


The GUI interface to disable pagefile across all NT based Windows OS-es is quite similar, the only difference is newer versions of Windows has slightly more options.


1.1 Disable pagefile on Windows XP


Quickest way is to find pagefile.sys settings from GUI menus

1. Computer (My Computer) – right click mouse
2. Properties (System Preperties will appear)
3. Advanced (tab) 
4. Settings
5. Advanced (tab)
6. Change button

windows-xp-pagefile-disable-screenshot

1.2 Disable pagefile on Windows 7

 

advanced-system-settings-control-panel-system-and-security-screenshot

windows-system-properties-screenshot-properties-advanced-change-Virtual-memory-pagefile-screenshot

system-properties-performance-options
 

Once applied you'll be required to reboot the PC

How-to-turn-off-Virtual-Memory-Paging_File-in-Windows-7-restart

 

1.3 Disable Increase / Decrease pagefile.sys on Windows 10 / Win 11
 

open-system-properties-advanced-win10

win10-performance-options-menu-screenshot

configure-virtual-memory-win-10-screenshot


1.4 Make Windows clear pagefile.sys on shutdown

On home PCs it might be useful thing to clear up ( nullify) pagefile.sys on shutdown, that could save you some disk space on every reboot, until file continuously grows to its configured Maximum.

Run

regedit

Modify registry key at location

 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

windows-clean-up-pagefile-sys-file-on-shutdown-or-reboot-registry-editor-value-screenshot

You can apply the value also via a registry file you can get the Enable Clearpagefile at shutdown here .reg.
 

2. Manipulating pagefile.sys size and file delete from command line with wmic tool 

For scripting purposes you might want to use the wmic pagefile which can do increase / decrase or delete the file without GUI, that is very helpful if you have to admin a Windows Domain (Active Directory)
 

[hipo.WINDOWS-PC] ➤ wmic pagefile /?

PAGEFILE – Virtual memory file swapping management.

HINT: BNF for Alias usage.
(<alias> [WMIObject] | [] | [] ) [].

USAGE:

PAGEFILE ASSOC []
PAGEFILE CREATE <assign list>
PAGEFILE DELETE
PAGEFILE GET [] []
PAGEFILE LIST [] []

 

[hipo.WINDOWS-PC] ➤ wmic pagefile
AllocatedBaseSize  Caption          CurrentUsage  Description      InstallDate                Name             PeakUsage  Status  TempPageFile
4709               C:\pagefile.sys  499           C:\pagefile.sys  20200912061902.938000+180  C:\pagefile.sys  525                FALSE

 

[hipo.WINDOWS-PC] ➤ wmic pagefile list /format:list

AllocatedBaseSize=4709
CurrentUsage=499
Description=C:\pagefile.sys
InstallDate=20200912061902.938000+180
Name=C:\pagefile.sys
PeakUsage=525
Status=
TempPageFile=FALSE

wmic-pagefile-command-line-tool-for-windows-default-output-screenshot

 

  • To change the Initial Size or Maximum Size of Pagefile use:
     

➤ wmic pagefileset where name="C:\\pagefile.sys" set InitialSize=2048,MaximumSize=2048

  • To move the pagefile / change location of pagefile to less occupied disk drive partition (i.e. D:\ drive)

     

     

    Sometimes you might have multiple drives on the PC and some of them might be having multitudes of gigabytes while main drive C:\ could be fully occupied due to initial install bad drive organization, in that case a good work arount to save you space so you can work normally with the server is just to temporary or permanently move pagefile to another drive.

wmic pagefileset where name="D:\\pagefile.sys" set InitialSize=2048,MaximumSize=2048


!! CONSIDER !!! 

That if you have the option to move the pagefile.sys for best performance it is advicable to place the file inside another physical disk, preferrably a Solid State Drive one, SATA disks are too slow and reduced Input / Output disk operations will lead to degraded performance, if there is lack of memory (i.e. pagefile.sys is actively open read and wrote in).
 

  • To delete pagefile.sys 
     

➤ wmic pagefileset where name="C:\\pagefile.sys" delete

 

If for some reason you prefer to not use wmic but simple del command you can delete pagefile.sys also by:

Removing file default "Hidden" and "system" file attributes – set for security reasons as the file is a system file usually not touched by user. This will save you from "permission denied" errors:
 

➤ attrib -s -h %systemdrive%\pagefile.sys


Delete the file:
 

➤ del /a /q %systemdrive%\pagefile.sys


3. Disable hibernation on Windows 7 / 8 and Win 10 / 11

Disabling hibernation file hiberfil.sys can also free up some space, especially if the hibernation has been actively used before and the file is written with data. Of course, that is more common on notebooks.
Windows hibernation has significantly improved over time though i didn't have very pleasant experience in the past and I prefer to disable it just in case.
 

3.1 Disable Windows 7 / 8 / 10 / 11 hibernation from GUI 

Disable it through:

Control Panel -> All Control Panel Items -> Power Options -> Edit Plan Settings -> Change advanced power settings


 like shown in below screenshot:

Windqows-power-options-Advanced-settings-Allow-Hybrid-sleep-option-menu-screenshot

 

3.2 Disable Windows 7 / 8 / 10 / 11 hibernation from command line

Disable hibernation Is done in the same way through the powercfg.exe command, to disable it
if you're cut of disk space and you want to save space from it:

run as Administrator in Command Line Windows (cmd.exe)
 

powercfg.exe /hibernate off

If you later need to switch on hibernation
 

powercfg.exe /hibernate on


disable-hiberfile-windows-screenshot

3.3 Disable Windows hibernation on legacy Windows XP

On XP to disable hibernation open

1. Power Options Properties
2. Select Hibernate
3. Select Enable Hibernation to clear the checkbox and disable Hibernation mode. 
4. Select OK to apply the change.

Close the Power Options Properties box. 

enable-disable-hibernate-windows-xp-menu-screenshot

To sum it up

We have learned some basics on Windows swapping and hibernation and i've tried to give some insight on how thiese files if misconfigured could lead to degraded Win OS performance. In any case using SSD as of 2022 to store both files is a best practice for machines that has plenty of memory always try to completely disable / remove the files. It was shown how  to manage pagefile.sys and hiberfil.sys across Windows Operating Systems different versions both from GUI and via command line as well as how you can configure pagefile.sys to be cleared up on pc reboot.
 

Set all logs to log to to physical console /dev/tty12 (tty12) on Linux

Wednesday, August 12th, 2020

tty linux-logo how to log everything to last console terminal tty12

Those who administer servers from the days of birth of Linux and who used actively GNU / Linux over the years or any other UNIX knows how practical could be to configure logging of all running services / kernel messages / errors and warnings on a physical console.

Traditionally from the days I was learning Linux basics I was shown how to do this on an old Debian Sarge 3.0 Linux without systemd and on all Linux distributions Redhat 9.0 / Calderas and Mandrakes I've used either as a home systems or for servers. I've always configured output of all messages to go to the last easy to access console /dev/tty12 (for those who never use it console switching under Linux plain text console mode is done with key combination of CTRL + ALT + F1 .. F12.

In recent times however with the introduction of systemd pretty much things changed as messages to console are not handled by /etc/inittab which was used to add and refresh physical consoles tty1, tty2 … tty7 (the default added one on Linux were usually 7), but I had to manually include more respawn lines for each console in /etc/inittab.
Nowadays as of year 2020 Linux distros /etc/inittab is no longer there being obsoleted and console print out of INPUT / OUTPUT messages are handled by systemd.
 

1. Enable Physical TTYs from TTY8 till TTY12 etc.


The number of default consoles existing in most Linux distributions I've seen is still from tty1 to tty7. Hence to add more tty consoles and be ready to be able to switch out  not only towards tty7 but towards tty12 once you're connected to the server via a remote ILO (Integrated Lights Out) / IdRAC (Dell Remote Access Controller) / IPMI / IMM (Imtegrated Management Module), you have to do it by telling systemd issuing below systemctl commands:
 

 

 # systemctl enable getty@tty8.service Created symlink /etc/systemd/system/getty.target.wants/getty@tty8.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty9.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty9.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty10.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty10.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty11.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty11.service -> /lib/systemd/system/getty@.service.

systemctl enable getty@tty12.service

Created symlink /etc/systemd/system/getty.target.wants/getty@tty12.service -> /lib/systemd/system/getty@.service.


Once the TTYS tty7 to tty12 are enabled you will be able to switch to this consoles either if you have a physical LCD / CRT monitor or KVM switch connected to the machine mounted on the Rack shelf once you're in the Data Center or will be able to see it once connected remotely via the Management IP Interface (ILO) remote console.
 

2. Taking screenshot of the physical console TTY with fbcat


For example below is a screenshot of the 10th enabled tty10:

tty10-linux-screenshot-fbcat-how-to-screenshot-console

As you can in the screenshot I've used the nice tool fbcat that can be used to make a screenshot of remote console. This is very useful especially if remote access via a SSH client such as PuTTY / MobaXterm is not there but you have only a physical attached monitor access on a DCs that are under a heavy firewall that is preventing anyone to get to the system remotely. For example screenshotting the physical console in case if there is a major hardware failure occurs and you need to dump a hardware error message to a flash drive that will be used to later be handled to technicians to analyize it and exchange the broken server hardware part.

Screenshots of the CLI with fbcat is possible across most Linux distributions where as usual.

In Debian you have to first instal the tool via :
 

# apt install –yes fbcat


and on RedHats / CentOS / Fedoras

# yum install -y fbcat


Taking screenshot once tool is on the server of whatever you have printed on console is as easy as

# fbcat > tty_name.ppm


Note that you might want to convert the .ppm created picture to png with any converter such as imagemagick's convert command or if you have a GUI perhaps with GNU Image Manipulation Tool (GIMP).

3. Enabling every rsyslog handled message to log to Physical TTY12


To make everything such as errors, notices, debug, warning messages  become instantly logging towards above added new /dev/tty12.

Open /etc/rsyslog.conf and to the end of the file append below line :
 

daemon,mail.*;\
   news.=crit;news.=err;news.=notice;\
   *.=debug;*.=info;\
   *.=notice;*.=warn   /dev/tty12


To make rsyslog load its new config restart it:

 

# systemctl status rsyslog

 

 

 

rsyslog.service – System Logging Service
   Loaded: loaded (/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2020-08-10 04:09:36 EEST; 2 days ago
     Docs: man:rsyslogd(8)
           https://www.rsyslog.com/doc/
 Main PID: 671 (rsyslogd)
    Tasks: 4 (limit: 4915)
   Memory: 12.5M
   CGroup: /system.slice/rsyslog.service
           └─671 /usr/sbin/rsyslogd -n -iNONE

 

авг 12 00:00:05 pcfreak rsyslogd[671]:  [origin software="rsyslogd" swVersion="8.1901.0" x-pid="671" x-info="https://www.rsyslo
Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.

 

systemctl restart rsyslog


That's all folks navigate by pressing simultaneously CTRL + ALT + F12 to get to TTY12 or use ALT + LEFT / ALT + RIGHT ARROW (console switch commands) till you get to the console where everything should be now logged.

Enjoy and if you like this article share to tell your sysadmin friends about this nice hack  ! 🙂

 

 

 

How to check how many processor and volume groups IBM AIX eServer have

Monday, July 13th, 2020

how-many-cpus-are-on-commands-Linux-sysadmin-and-user-show-know-AIX-logo
In daily sysadmin duties I have been usually administrating GNU / Linux or FreeBSD servers.
However now in my daily sysadmin jobs I've been added to do some minor sysadmin activities on  a few IBM AIX eServers UNIX machines.

As the eServers were completely unknown to me and I logged in for a first time I needed a way to get idea on what kind of hardware I'm logging in so I wanted to get information about the Central Processing UNIT CPUs on the host.

On Linux I'm used to do a cat /proc/cpuinfo or do dmidecode etc. to get the number of CPUs, however AIX does not have /proc/cpuinfo and has its own way to get information about the system hardware.
As I've red in the IBM AIX's RedBook to get system information on AIX there is the lscfg command.
 

aix:/# lscfg
INSTALLED RESOURCE LIST

The following resources are installed on the machine.
+/- = Added or deleted from Resource List.
*   = Diagnostic support not available.

  Model Architecture: chrp
  Model Implementation: Multiple Processor, PCI bus

+ sys0                                                            System Object
+ sysplanar0                                                      System Planar
* vio0                                                            Virtual I/O Bus
* vscsi3           U8205.E6B.068D6AP-V4-C21-T1                    Virtual SCSI Client Adapter
* vscsi2           U8205.E6B.068D6AP-V4-C20-T1                    Virtual SCSI Client Adapter
* vscsi1           U8205.E6B.068D6AP-V4-C11-T1                    Virtual SCSI Client Adapter
* hdisk1           U8205.E6B.068D6AP-V4-C11-T1-L8100000000000000  Virtual SCSI Disk Drive
* vscsi0           U8205.E6B.068D6AP-V4-C10-T1                    Virtual SCSI Client Adapter
* hdisk0           U8205.E6B.068D6AP-V4-C10-T1-L8100000000000000  Virtual SCSI Disk Drive
* ent3             U8205.E6B.068D6AP-V4-C5-T1                     Virtual I/O Ethernet Adapter (l-lan)
* ent2             U8205.E6B.068D6AP-V4-C4-T1                     Virtual I/O Ethernet Adapter (l-lan)
* ent1             U8205.E6B.068D6AP-V4-C3-T1                     Virtual I/O Ethernet Adapter (l-lan)
* ent0             U8205.E6B.068D6AP-V4-C2-T1                     Virtual I/O Ethernet Adapter (l-lan)
* vsa0             U8205.E6B.068D6AP-V4-C0                        LPAR Virtual Serial Adapter
* vty0             U8205.E6B.068D6AP-V4-C0-L0                     Asynchronous Terminal
+ L2cache0                                                        L2 Cache
+ mem0                                                            Memory
+ proc0                                                           Processor
+ proc4                                                           Processor


To get the number of processors on the host I've had to use:

 

aix:/# lscfg|grep -i proc
  Model Implementation: Multiple Processor, PCI bus
+ proc0                                                           Processor
+ proc4                                                           Processor


Another way to get the CPU number is with:

aix:/# lsdev -C -c processor
proc0 Available 00-00 Processor
proc4 Available 00-04 Processor

 

aix:/# lsattr -EH -l proc4
attribute   value          description           user_settable

 

frequency   3720000000     Processor Speed       False
smt_enabled true           Processor SMT enabled False
smt_threads 4              Processor SMT threads False
state       enable         Processor state       False
type        PowerPC_POWER7 Processor type        False

aix:/# lsattr -EH -l proc0
attribute   value          description           user_settable

 

frequency   3720000000     Processor Speed       False
smt_enabled true           Processor SMT enabled False
smt_threads 4              Processor SMT threads False
state       enable         Processor state       False
type        PowerPC_POWER7 Processor type        False


As you can see each of the processor is multicore has 2 Cores and each of the cores have for Threads, to get the overall number of CPUs on the system including the threaded Virtual CPUs:

aix:/# bindprocessor -q
The available processors are:  0 1 2 3 4 5 6 7


This specific machine has overall of 8 CPUs cores.

lscfg can be used to get various useful other info of the iron:

aix:/# lscfg -s
INSTALLED RESOURCE LIST

 

The following resources are installed on the machine.
+/- = Added or deleted from Resource List.
*   = Diagnostic support not available.

  Model Architecture: chrp
  Model Implementation: Multiple Processor, PCI bus

+ sys0
        System Object
+ sysplanar0
        System Planar
* vio0
        Virtual I/O Bus
* vscsi3           U8305…………….
        Virtual SCSI Client Adapter
* vscsi2           U8305…………….
        Virtual SCSI Client Adapter
* vscsi1           U8305…………….
        Virtual SCSI Client Adapter
* hdisk1           U8305…………….
        Virtual SCSI Disk Drive
* vscsi0           U8305……………..
        Virtual SCSI Client Adapter
* hdisk0           U8305…………….
        Virtual SCSI Disk Drive
* ent3             U8305…………….
        Virtual I/O Ethernet Adapter (l-lan)
* ent2             U8305.E6B…………….
        Virtual I/O Ethernet Adapter (l-lan)
* ent1             U8305.E6B…………….
        Virtual I/O Ethernet Adapter (l-lan)
* ent0             U8305.E6B…………….
        Virtual I/O Ethernet Adapter (l-lan)
* vsa0             U8305.E7B…………….
        LPAR Virtual Serial Adapter
* vty0             U8305.E7B…………….
        Asynchronous Terminal
+ L2cache0
        L2 Cache
+ mem0
        Memory
+ proc0
        Processor
+ proc4
        Processor

aix:/# lscfg -p
INSTALLED RESOURCE LIST

The following resources are installed on the machine.

  Model Architecture: chrp
  Model Implementation: Multiple Processor, PCI bus

  sys0                                                            System Object
  sysplanar0                                                      System Planar
  vio0                                                            Virtual I/O Bus
  vscsi3           U8305.E7B…………….V6-C40-T1                    Virtual SCSI Client Adapter
  vscsi2           U8305.E7B…………….V6-C40-T1                     Virtual SCSI Client Adapter
  vscsi1           U8305.E7B…………….V6-C40-T1                    Virtual SCSI Client Adapter
  hdisk1           U8305.E7B…………….V6-C40-T1-L8500000000000000  Virtual SCSI Disk Drive
  vscsi0           U8305.E7B…………….V6-C40-T1                    Virtual SCSI Client Adapter
  hdisk0           U8305.E7B…………….V6-C40-T1-L8500000000000000  Virtual SCSI Disk Drive
  ent3             U8305.E7B…………….V6-C40-T1                     Virtual I/O Ethernet Adapter (l-lan)
  ent2             U8305.E7B…………….V6-C40-T1                     Virtual I/O Ethernet Adapter (l-lan)
  ent1             U8305.E7B…………….V6-C40-T1                     Virtual I/O Ethernet Adapter (l-lan)
  ent0             U8305.E7B…………….V6-C40-T1                     Virtual I/O Ethernet Adapter (l-lan)
  vsa0             U8305.E7B.069D7AP-V5-C1                        LPAR Virtual Serial Adapter
  vty0             U8305.E7B.069D7AP-V5-D1-L0                     Asynchronous Terminal
  L2cache0                                                        L2 Cache
  mem0                                                            Memory
  proc0                                                           Processor
  proc4                                                           Processor

  PLATFORM SPECIFIC

  Name:  IBM,8305-E7B
    Model:  IBM,8305-E7B
    Node:  /
    Device Type:  chrp

  Name:  openprom
    Model:  IBM,AL730_158
    Node:  openprom

  Name:  interrupt-controller
    Model:  IBM, Logical PowerPC-PIC, 00
    Node:  interrupt-controller@0
    Device Type:  PowerPC-External-Interrupt-Presentation

  Name:  vty
    Node:  vty@30000000
    Device Type:  serial
    Physical Location: …………………………………………..

  Name:  l-lan
    Node:  l-lan@30000002
    Device Type:  network
    Physical Location: …………………………………………..

  Name:  l-lan
    Node:  l-lan@30000003
    Device Type:  network
    Physical Location: …………………………………………..

  Name:  l-lan
    Node:  l-lan@30000004
    Device Type:  network
    Physical Location: …………………………………………..

  Name:  l-lan
    Node:  l-lan@30000005
    Device Type:  network
    Physical Location: …………………………………………..

  Name:  v-scsi
    Node:  v-scsi@3000005a
    Device Type:  vscsi
    Physical Location: …………………………………………..

  Name:  v-scsi
    Node:  v-scsi@3000005b
    Device Type:  vscsi
    Physical Location: …………………………………………..

  Name:  v-scsi
    Node:  v-scsi@30000014
    Device Type:  vscsi
    Physical Location: ………………………………..

  Name:  v-scsi
    Node:  v-scsi@30000017
    Device Type:  vscsi
    Physical Location: …………………………………

 


Another useful command I found is to list the equivalent of Linux's LVM Logical Volumes configured on the system, below is how:

aix:/# lspv hdisk0
00f68c6a84acb0d5 rootvg active hdisk1 00f69d6a85400468 dsvg active

To get more info on a volume group:

aix:/# lspv hdisk0 PHYSICAL VOLUME: hdisk0 VOLUME GROUP: rootvg PV IDENTIFIER: 00f68d6a85acb0d5 VG IDENTIFIER 00f68d6a00004c0000000131353444a5 PV STATE: active STALE PARTITIONS: 0 ALLOCATABLE: yes PP SIZE: 32 megabyte(s) LOGICAL VOLUMES: 12 TOTAL PPs: 959 (30688 megabytes) VG DESCRIPTORS: 2 FREE PPs: 493 (15776 megabytes) HOT SPARE: no USED PPs: 466 (14912 megabytes) MAX REQUEST: 256 kilobytes FREE DISTRIBUTION: 191..00..00..110..192 USED DISTRIBUTION: 01..192..191..82..00 MIRROR POOL: None


You can get which local configured partition is set on which ( PV )Physical Volume

aix:/# lspv -l hdisk0
hdisk0:
LV NAME               LPs     PPs     DISTRIBUTION          MOUNT POINT
lg_dumplv             64      64      00..64..00..00..00    N/A
hd8                   1       1       00..00..01..00..00    N/A
hd6                   16      16      00..16..00..00..00    N/A
hd2                   166     166     00..45..89..32..00    /usr
hd4                   29      29      00..11..18..00..00    /
hd3                   40      40      00..04..04..32..00    /tmp
hd9var                55      55      00..00..37..18..00    /var
hd10opt               74      74      00..37..37..00..00    /opt
hd1                   8       8       00..07..01..00..00    /home
hd5                   1       1       01..00..00..00..00    N/A

Start Event Viewer from Command Line (Prompt) – eventvwr.msc to Debug Windows server issues

Friday, November 6th, 2015

eventvwrmsc-event-viewer-windows-7-screenshot-view-windows-log-and-dianose-errors

If you’re a sysadmin which needs to deal with Microsoft Windows servers locally or remotely via Remote Desktop RDP client (MSTSC.EXE) or inside a Windows Domain Controller, you will have to frequently debug Windows isseus or Application caused errors by reviewing debug information stored in Event Logs.

Event Viewer is a precious tool to debug often errors with missing libraries or failing programs on Windows boot and thus on M$ Windows it is the Swiss Army knife of sysadmin.
However as staring Event Viewer using the GUI menus, takes a lot of step and looses you time, e.g., you have to navigate to menus:

1. Start button Picture of the Start button
2. clicking Control Panel
3. clicking System and Security
4. clicking Administrative Tools
5.then double-clicking Event Viewer.‌
6. Granting Administrator permission required If you’re prompted for an administrator password or confirmation

It is much handier to just start it with a shortcut:

Press Windows (Button) + R
– To invoke run prompt

and type:

eventvwr.msc

In case if you’re running eventvwr.msc to connect to remote Windows Server run from command prompt (cmd.exe):

eventvwr-run-from-command-prompt-with-a-smart-shortcut-to-save-time-when-administrating-windows-servers

eventvwr.msc /computer=OTHER_Computer_Name

event-viewer-log-reader-and-debug-tool-for-windows-PC-and-windows-servers-adminsitration

Check Windows load avarage command – Get CPU usage from Windows XP / 7 / 8 / 2012 server cmd prompt

Wednesday, August 19th, 2015

Check_Windows-load-avarage-command-Get_CPU_usage_from_Windows_XP-7-8-2003-2010-2012_server_cmd_prompt

If you used to be a long years Linux / UNIX sysadmin and you suddenly have to also admistrate a bunch of Windows hosts via RDP (Remote Desktop Protocol)  / Teamviewer etc. and you need to document The Load Avarage of a Windows XP / 7 / 8 servers but you're puzzled how to get an overall load avarage of Windows host via command in a UNIX way like with the good old uptime  Linux / BSD command e.g.

 ruth:$ uptime
 11:43  up 713 days 22:44,  1 user,  load average: 0.22, 0.17, 0.15

Then its time to you to get used to WMICWMIC extends WMI for operation from several command-line interfaces and through batch scripts. wmic is a wonderful command for Command addicted Linux guys and gives a lot of opportunities to query and conduct various sysadmin tasks from Windows command prompt.

To get an loadavarage with wmic use:
 

C:\>wmic cpu get loadpercentage
LoadPercentage
1

 


or
 

@for /f "skip=1" %p in ('wmic cpu get loadpercentage') do @echo %p%
1%
%

 

on Windows 7 / 8 and 10 as well Windows Server 2010 and Windows Server 2012 for more precise CPU loadavarage results, you can also use:
 

C:\> typeperf "\processor(_total)\% processor time"

"(PDH-CSV 4.0)","\\Win-Host\processor(_total)\% processor time"
"08/19/2015 12:52:53.343","0.002288"
"08/19/2015 12:52:54.357","0.000000"
"08/19/2015 12:52:55.371","0.000000"
"08/19/2015 12:52:56.385","0.000000"
"08/19/2015 12:52:57.399","0.000799"
"08/19/2015 12:52:58.413","0.000000"
"08/19/2015 12:52:59.427","0.000286"
"08/19/2015 12:53:00.441","0.000000"
"08/19/2015 12:53:01.455","0.000000"
"08/19/2015 12:53:02.469","0.008678"
"08/19/2015 12:53:03.483","0.000000"
"08/19/2015 12:53:04.497","0.002830"
"08/19/2015 12:53:05.511","0.000621"
"08/19/2015 12:53:06.525","0.768834"
"08/19/2015 12:53:07.539","0.000000"
"08/19/2015 12:53:08.553","1.538296"

 

Adding another level of security to your shared Debian Linux webhosting server with SuPHP

Tuesday, April 7th, 2015

suphp_improve-apache-security-protect-against-virus-internal-server-infections-suphp-webserver-logo

There are plenty of security schemes and strategies you can implement if you're a Shared Web Hosting company sysadmin however probably the most vital one is to install on Apache + PHP Webserver SuPHP module.

# apt-cache show suphp-common|grep -i descrip -A 4

Description: Common files for mod suphp Suphp consists of an Apache module (mod_suphp for either Apache 1.3.x or Apache 2.x) and a setuid root binary (suphp) that is called by the Apache module to change the uid of the process executing the PHP interpreter to the owner of the php script.

So what SuPHP actuall  does is to run separate CPanel / Kloxo etc. Users with separate username and groupid permissions coinciding with the user present in /etc/passwd , /etc/shadow files existing users, thus in case if someone hacks some of the many customer sites he would be able to only write files and directories under the user with which the security breach occured.

On servers where SuPHP is not installed, all  systemusers are using the same UserID / GuID to run PHP executable scripts under separate domains Virtualhost which are coinciding with Apache (on Debian / Ubuntu  uid, gid – www-data) or on (CentOS / RHEL / Fedora etc. – user apache) so once one site is defaced  exploited by a worm all or most server websites might end up infected with a Web Virus / Worm which will be trying to exploit even more sites of a type running silently in the background.  This is very common scenarios as currently there are donezs of PHP / CSS / Javasripts / XSS vulnerability exploited on VPS and Shared hosting servers due to failure of a customer to update his own CMS  scripts / Website  (Joomla, Wordpress, Drupal etc.) and the lack of resource to regularly monitor all customer activities / websites.

Therefore installing SuPHP Apache module is essential one to install on new serverslarge hosting providers as it saves the admin a lot of headache from spreading malware across all hosted servers sites ..
Some VPS admins that are security freaks tend to also install SuPHP module together with many chrooted Apache / LiteSpeed / Nginx webservers each of which running in a separate Jailed environment.

Of course using SuPHP besides giving a improved security layer to the webserver has its downsides such as increased load for the server and making Apache PHP scripts being interpretted a little bit slower than with plain Apache + PHP but performance difference while running a site on top of SuPHP is often not so drastic so you can live it up ..

Installing SuPHP on a Debian / Ubuntu servers is a piece of cake, just run the as root superuser, usual:
 

# apt-get install libapache2-mod-suphp


Once installed only thing to make is to turn off default installed Apache PHP module (without SuPHP compiled support and restart Apache webserver):
 

# a2dismod php5 …

# /etc/init.d/apache2 restart


To test the SuPHP is properly working on the Apache Webserver go into some of many hosted server websites DocumentRoot

And create new file called test_suphp.php with below content:

# vim test_suphp.php
<?php
system('id');
?>

Then open in browser http://whatever-website/test_suphp.php assuming that system(); function is not disabled for security reasons in php.ini you should get an User ID, GroupID bigger than reserved system IDs on GNU / Linux e.g. ID > UID / GID 99

Its also a good idea to take a look into SuPHP configuration file /etc/suphp/suphp.conf and tailor options according to your liking 

If different hosted client users home directories are into /home directory, set in suphp.conf

;Path all scripts have to be in

docroot=/home/


Also usually it is a good idea to set 

umask=0022 

Monitoring CPU load and memory usage on Mac OS X command line (Terminal)

Thursday, July 3rd, 2014

macosx-server-screenshot-server-assistant-apple-tool
You might be stunned to find out Mac OS X has a server variant called Mac OS X server. For the usual admin having to administer a Mac OS X based server is something rarely to do, however it might happen some day, and besides that nowadays Mac OS X has about 10% percentage share of PC desktop and laptops used on the Internet (data collected from w3cschools log files). Thus cause it is among popular OSes, it very possible sooner or later as a sysadmin you will have to troubleshoot issues on at least Mac OS X notebook. Mac has plenty of instruments to debug OS issues as it is UNIX (BSD) based

Mac OS X has already a GUI tool called Activity Monitor (existing in Mac OS 10.3 onwards) in earlier verions, there was tool called Process Viewer and CPU Monitor.

To start Activity Monitor open Finder and launch it via:

Applications -> Utilities -> Activity Monitor

As a Linux guy, I like to use command line and there Mac OS X is equipped with a good arsenal of tools to check CPU load and Memory. Mac OS X comes with sar – (system activity reporter), top (process monitor) and vm_stat (virtual memory statistics) command – these ones are equivalent of Linux's sar (from sysstats package), top and Linux vmstat (report virtual memory statistics).

1. Check out Mac OS X HDD Input / Output statistics
 

$ sar -d -f ~/output.sar

20:43:18   device    r+w/s    blks/s
New Disk: [disk0] IODeviceTree:/PCI0@0/RP06@1C,5/SSD0@0/PRT0@0/PMP@0/@0:0
New Disk: [disk1] IOService:/IOResources/IOHDIXController/IOHDIXHDDriveOutKernel@1/IODiskImageBlockStorageDeviceOutKernel/IOBlockStorageDriver/Apple UDIF, только для чтения, сжатый (zlib)
New Disk: [disk2] IOService:/IOResources/IOHDIXController/IOHDIXHDDriveOutKernel@3/IODiskImageBlockStorageDeviceOutKernel/IOBlockStorageDriver/Apple UDIF, только для чтения, сжатый (bzip2)
New Disk: [disk3] IOService:/IOResources/IOHDIXController/IOHDIXHDDriveOutKernel@4/IODiskImageBlockStorageDeviceOutKernel/IOBlockStorageDriver/Apple UDIF, только для чтения, сжатый (bzip2)
New Disk: [disk4] IOService:/IOResources/IOHDIXController/IOHDIXHDDriveOutKernel@6/IODiskImageBlockStorageDeviceOutKernel/IOBlockStorageDriver/Apple UDIF, только для чтения, сжатый (zlib)
20:43:28   disk0        7        312
20:43:28   disk1        0          0
20:43:28   disk2        0          0
20:43:28   disk3        0          0
20:43:28   disk4        0          0
20:43:38   disk0       12        251
20:43:38   disk1        0          

2. Checking Mac OS X CPU Load from terminal

To check Load from Mac OS command line use:
 

$ sar -o ~/output.sar 10 10

That gathers 10 sets of metrics at 10 second intervals. You can then extract useful information from the output file (even while it's still running), this will get you cpu load on Mac OS system spitting stats every 10 seconds.

 

21:22:33  %usr  %nice   %sys   %idle
21:22:43    7      0      2     90
21:22:53    8      0      3     89
21:23:03   11      0      4     85
21:23:13    9      0      3     88
21:23:23    9      0      3     88
21:23:33    7      0      3     90
21:23:43   10      0      3     87
21:23:53   10      0      4     85
21:24:03   10      0      5     85
21:24:13    8      0      3     88
Average:      8      0      3     87   


3. Checking Free memory on  Mac OS X

Use this obscure one liner to free -m Linux memory command like output from Mac terminal

$ vm_stat | perl -ne '/page size of (d+)/ and $size=$1; /Pagess+([^:]+)[^d]+(d+)/ and printf("%-16s % 16.2f Min", "$1:", $2 * $size / 1048576);'
 

free: 43.38 Mi
active: 1762.00 Mi
inactive: 1676.91 Mi
speculative: 3.29 Mi
wired down: 609.38 Mi
copy-on-write: 29431.01 Mi
zero filled: 4687689.80 Mi
reactivated: 30288.86 Mi


To show inactive memory in Gigabytes every 10 seconds

$ vm_stat 10 | awk 'NR>2 {gsub("K","000");print ($1+$4)/256000}'

1.70532
1.70455
1.70389
1.6904

 

It is also possible to get memory statistics on Mac PC running top in non-interactive mode and grepping it from output:

$ top -l 1 | head -n 10 | grep PhysMem | sed 's/, /n /g'

 

PhysMem: 599M wired, 1735M active, 1712M inactive, 4046M used, 47M free.

 

4. Quick command to get Kernel / how many CPUs, available memory and load avarage on Mac OS X

From y. 2003 onwards of Mac OS have hostinfo(host information) command, providing admin with quick way to get System Info on Mac OS

$ hostinfo

 

Mach kernel version:
Darwin Kernel Version 12.5.0: Sun Sep 29 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64
Kernel configured for up to 4 processors.
2 processors are physically available.
4 processors are logically available.
Processor type: i486 (Intel 80486)
Processors active: 0 1 2 3
Primary memory available: 4.00 gigabytes
Default processor set: 98 tasks, 621 threads, 4 processors
Load average: 1.63, Mach factor: 2.54

 


If you need more verbose information on system hardware and resources, check out system_profiler. As the manual describes it, system_profiler(reports system hardware and software configuration.) cmd:

$ system_profiler Here is a link to output file generated by system_prifler

 

 

What is Vertical scaling and Horizontal scaling – Vertical and Horizontal hardware / services scaling

Friday, June 13th, 2014

horizontal-vs-vertical-scaling-vertical-and-horizontal-scaling-explained-diagram

If you're coming from a small or middle-sized company to a corporations like HP or IBM probably you will not a clear defined idea on the 2 types (2 dimensions) of system Scaling (Horizontal and Vertical scaling). I know from my pesronal experience that in small companies – all needed is to guarantee a model for as less probels as possible without too much of defining things and with much less planning. Other thing is being a sysadmin in middle-sized companies, often doesn't give you opportunity to discuss issues to solve with other admins but you have to deal as "one man (machine) for all" and thus often to solve office server and services tasks you do some custom solution.
hence for novice system administrators probably it will be probably unclear what is the difference between Horizontal and Vertical Scaling?

horizontal-vertical-scaling-scale-up-and-scale-out-server-infrastructure-diagram

 

Vertical Scaling (scale vertically or scale up) :- adding more resources(CPU/RAM/DISK) to your server (database or application server is still remains one).
Vertical Scaling is much more used in small and middle-sized companies and in applications and products of middle-range. Very common example for Virtual Scaling nowdays is to buy an expensive hardware and use it as a Virtual Machine hypervisor (VMWare ESX). Where a database is involved using Vertical Scaling without use of multiple virtual machines might be not the best solution, as even though hardware might suffice (creation of database locks might impose problems). Reasons to scale vertically include increasing IOPS (Input / Ouput Operations), increasing CPU/RAM capacity, and increasing disk capacity.
Because Vertical Scaling usually means upgrade of server hardware – whenever an improved performance is targeted, even though if Virtualization is used, the risk for downtimes with it is much higher than whenever horizontal scaling.

Horizontal Scaling (scale horizontally or scale out):- adding more processing units (phyiscal machine) to your server (infrastructure be it application web/server or database).
Horizontal scaling, means increasing  the number of nodes in the cluster, reduces the responsibilities of each member node by spreading the keyspace wider and providing additional end-points for client connections. The capacity of each individual node does not change, but its load is decreased (because load is distributed between separate server nodes). Reasons to scale horizontally include increasing I/O concurrency, reducing the load on existing nodes, and increasing disk capacity.
Horizontal Scaling has been historically much more used for high level of computing and for application and services. The Internet and particular web services gave a boom of Horizontal Scaling use, most companies nowadays that provide well known web services like Google (Gmail, Youtube), Yahoo, Facebook, Ebay, Amazon etc. are using heavily horizontal scaling. Horizontal Scaling is a must use technology – whenever a high availability of (server) services are required.

mod_rewrite redirect rule 80 to 443 on Apache webserver

Wednesday, April 2nd, 2014

A classic sysadmin scenario is to configure new Apache webserver with requirement to have an SSL ceriticate installed and working on port 443 and all requests coming on port 80 to be redirected to https://.
On Apache this is done with simple mod_rewrite rule:

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

Before applying the rule don't forget to have Apache mod_rewrite enabled usually it is not enabled on default most Linux distributions by default.
On shared hostings if you don't have access to directly modify Apache configuration but have .htaccess enabled you can add above rules also to .htaccess

Add this to respective VirtualHost configuration and restart Apache and that's it. If after configuring it for some reason it is not working debug mod_rewrite issues by enabling mod_rewrite's rewrite.log

Other useful Apache mod_rewrite redirect rule is redirect a single landing page from HTTP to HTTP

RewriteEngine On
RewriteRule ^apache-redirect-http-to-https.html$ https://www.site-url.com/apache-redirect-http-to-https.html [R=301,L]

!Note! that in case where performance is a key requirement for a website it might be better to use the standard way to redirect HTTP to HTTPS protocol in Apache through:

ServerName www.site-url.com Redirect / https://www.site-url.com/

To learn more on mod_rewrite redirecting  check out this official documentation on Apache's official site.

Preventing packages on Debian and Ubuntu Linux to not update on system updates

Wednesday, March 6th, 2013

On Debian based GNU / Linux distros, there are some critical packages which need to be disabled to update during the common routine apt-get update && apt-get upgrade which is a almost daily part of Debian sysadmin living. Example for packages which are good to mark not to upgrade are for example; linux kernel, java virtual machine, adobe flash plugin,  etc.

Setting a package to omit upgrade on system package update for adobe flash plugin for example is with:

# echo adobe-flashplugin hold | dpkg –set-selections
debian:~# echo adobe-flash-properties-gtk hold | dpkg --set-selections
debian:~# echo flashplugin-nonfree-extrasound hold | dpkg --set-selections

To do deb package update on hold for kernel;

 

debian:~# echo linux-image-generic hold | dpkg --set-selections
debian:~# echo linux-image-3.2.0-38-generic | dpkg --set-selections

Do the same for as many packages which seem to break up on updates and when, you explicitly want remove the hold/s run:

debian:~# echo adobe-flashplugin install | dpkg --set-selections
....
debian:~# echo linux-image-generic install | dpkg --set-selections