Posts Tagged ‘amazement’

Fix to sfc /scannow (System File Checker) error “The specific code is 0x000006ba [The RPC Server is unavailable.] “

Friday, December 14th, 2012

I had to fix one Windows XP computer today. The computer was in a terrible state (meak to say), the system was hanging during boot,

None of Windows recovery modes worked,  except when running it through:

Windows Safe Mode (With Command Prompt) mode (pressing F8 before Windows boot with Windows flag screen).

I followed some Usual commands to repair broken Windows XP, as the system was hanging during boot there was obviously some issues with corrupt by Viruses and Malware system binary (.exe) files or some .DLL was substituted in (C:WindowsSystem32 and C:WindowsSystem32DllCacache) with a trojanned version by some "bad ware". 

Thus the logical thing to do was to try:

sfc /scannow

from Safe Mode's cmd prompt. Instead of starting its work as usual System File Checker spitted an error:

Windows File Protection could not be initiate a scan of protected system files. 
The specific code is 0x000006ba [The RPC Server is unavailable.]

You can guess my amazement as I see this error for a first time in my life. Actually I don't remember if I run System File Checker scan from a Safe Mode With only Command Prompt ever so I'm not sure if this error was caused by some Virus activity which broke up the Win host, or it is due to the fact RCP Services are not loaded in Safe Mode – With Command Prompt Only.

As the message implies RCP Server is not running and sfc depends on it.

The reason for the error is Windows File Protection (WFP) was disabled by some of the Spyware or Viruses which infested the poor Win PC.

As the problem consisted in unworking RPC Services I tried launching RPC manually with command:

> net start rpcss  

This unfortunately did not succeeded (dunno why).

I've later seen another fix pointed on a couple of forums around, which is using Registry to enable SFC.

Re-enabling SFC is done by:

1. Launching regedit

2. Once launched go to the following reg settings (sub-values)

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWinlogon

Use modify on it and change value to be "0"
3. Restart windows and launch again Safe Mode With (Command Prompt Only)

There execute:

> sfc /purgecache
> sfc /scannow

This solves it however, as you never can be sure if the Install time .DLLs are not already rootkited by the Virus-es and Spywares which "posessed" the computer. It is generally a good idea to Launch the Windows Install CD, recovery console and launch SFC using it, or even try using the Windows CD (Repair) mode. Though this is a temporary work around, this system will need a re-install in very short future, or it will most likely came in the same broken state in a very while – I don't believe such an infested computer can be "cured" except with a clean CD Windows re-install.
If this method didn't work for you but something else worked for you, whether you had to fix a Win PC please drop a comment with the solution.

How to solve “Incorrect key file for table ‘/tmp/#sql_9315.MYI’; try to repair it” mysql start up error

Saturday, April 28th, 2012

When a server hard disk scape gets filled its common that Apache returns empty (no content) pages…
This just happened in one server I administer. To restore the normal server operation I freed some space by deleting old obsolete backups.
Actually the whole reasons for this mess was an enormous backup files, which on the last monthly backup overfilled the disk empty space.

Though, I freed about 400GB of space on the the root filesystem and on a first glimpse the system had plenty of free hard drive space, still restarting the MySQL server refused to start up properly and spit error:

Incorrect key file for table '/tmp/#sql_9315.MYI'; try to repair it" mysql start up error

Besides that there have been corrupted (crashed) tables, which reported next to above error.
Checking in /tmp/#sql_9315.MYI, I couldn't see any MYI – (MyISAM) format file. A quick google look up revealed that this error is caused by not enough disk space. This was puzzling as I can see both /var and / partitions had plenty of space so this shouldn't be a problem. Also manally creating the file /tmp/#sql_9315.MYI with:

server:~# touch /tmp/#sql_9315.MYI

Didn't help it, though the file created fine. Anyways a bit of a closer examination I've noticed a /tmp filesystem mounted besides with the other file system mounts ????
You can guess my great amazement to find this 1 Megabyte only /tmp filesystem hanging on the server mounted on the server.

I didn't mounted this 1 Megabyte filesystem, so it was either an intruder or some kind of "weird" bug…
I digged in Googling to see, if I can find more on the error and found actually the whole mess with this 1 mb mounted /tmp partition is caused by, just recently introduced Debian init script /etc/init.d/mountoverflowtmp.
It seems this script was introduced in Debian newer releases. mountoverflowtmp is some kind of emergency script, which is triggered in case if the root filesystem/ space gets filled.
The script has only two options:

# /etc/init.d/mountoverflowtmp
Usage: mountoverflowtmp [start|stop]

Once started what it does it remounts the /tmp to be 1 megabyte in size and stops its execution like it never run. Well maybe, the developers had something in mind with introducing this script I will not argue. What I should complain though is the script design is completely broken. Once the script gets "activated" and does its job. This 1MB mount stays like this, even if hard disk space is freed on the root partition – / ….

Hence to cope with this unhandy situation, once I had freed disk space on the root partition for some reason mountoverflowtmp stop option was not working,
So I had to initiate "hard" unmount:

server:~# mount -l /tmp

Also as I had a bunch of crashed tables and to fix them, also issued on each of the broken tables reported on /etc/init.d/mysql start start-up.

server:~# mysql -u root -p
mysql> use Database_Name;
mysql> repair table Table_Name extended;

Then to finally solve the stupid Incorrect key file for table '/tmp/#sql_XXYYZZ33444.MYI'; try to repair it error, I had to restart once again the SQL server:

Stopping MySQL database server: mysqld.
Starting MySQL database server: mysqld.
Checking for corrupt, not cleanly closed and upgrade needing tables..

Tadadadadam!, SQL now loads and works back as before!