Category Archives: Servers

Linux : Centrify adclient ERROR base.adagent Can’t use default machine password. Please reset computer account in Active Directory.

Whatever you’ve been using Centrify for a month or years on a Linux machine joined to an Active Directory Domain Controller, login using an AD user might suddenly stop work and display the following error message in the system logs (/var/log/message) : adclient[4933]: INFO <bg:ageBindings> base.bind.healing Lost connection to pdc.ad-forest.domain.tld. Running in disconnected mode: KDC refused… Read More »

Windows : Computer cannot be managed

Starting with Windows Server 2008 R2/2012, the fancy remote management feature may return the following error when adding to your centralized Server Manager console : Computer <NAME> cannot be managed. Verify that the network path is correct, the computer is available on the network and that the appropriate Windows Firewall rules are enabled on the… Read More »

Linux : High speed Rsync file transfer

If you have a large amount of data to transfer over the network to another server, Rsync is definately a good way to go. However, since Rsync is using SSH, data encryption can add an extra bottle neck to your speed transfer. You may want to disable encryption if you are transfering locally or if… Read More »

Linux : Oracle unbreakable kernel and OCFS2 on CentOS/RHEL6

Oracle Cluster File System 2 (well known as OCFS2) is a pretty decent choice when come to chose a filesystem that need to be accessed and written using several server nodes. Unfortunately, RedHat do not support by default OCFS2 in their kernel since they are using GFS instead. I am not aware of any unofficial… Read More »

Linux : R1Soft snapshot failed with error ‘FILE IO ERROR’!

Having this error on your R1Soft policy for a one or several servers? Error replicating device <PARTITION_MOUNTPOINT> (<PARTITION_UUID>) Protocol error, expected request finished Encountered <0000> read failures! Snapshot failed with error ‘FILE IO ERROR’! An exception occurred during the request. Backup failed due to snapshot error! The next replication will force a full block scan. This is likely… Read More »

Linux : MySQL InnoDB: Operating system error number 13 in a file operation

Have you encountered the following error starting MySQL server on a new machine that you’ve copied over the databases folder from another server? 140612 21:38:29 mysqld started 140612 21:38:29 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB:… Read More »

Windows : Shared printer exist but not shown in Devices and Printers

I had this interesting issue lately on Windows Server 2008 R2 where the shared printer just vanishing from the directory/shares on and off. Here is what I did to resolve this issue. If you do not have the Print Server role installed, you will need the Print Management Tools to actually view all your printers.… Read More »

Linux : APC usage and hit ratio information page

APC (Alternative PHP Cache) come with a nice script (apc.php) that will sort and show you the memory usage and hit ratio of pages cached into APC memory. Do these easy steps to set this up on your Web server. Copy the script from APC folder into a vHost on your Web server (this example… Read More »

Linux : Install file_cache_module.so on CentOS/RHEL6

Since CentOS/RedHat Enterprise Linux 6, “mod_file_cache”, commonly referred as “MMapFile” too is no longer provided with Apache binary. File Cache module statically map file pages into memory. This module is still experimental according to Apache documentation, which may explain why it’s not included, even though it was included in CentOS/RHEL5. You may get the following… Read More »

Linux : PHP Warning: Unable to allocate memory for pool

Found this error in your Web site Apache error logs? PHP Warning: require_once(): Unable to allocate memory for pool. This is actually caused by APC (Alternative PHP Cache). The allocated memory limit for APC has been reached and no additional PHP script can be cached anymore. The symptoms on your Web site for such error… Read More »