blog.erben.sk Just another sysadmin blog

4Nov/100

Slow Drupal on NFS

Drupal includes many files. When DocumentRoot is hosted on NFS, include calls are slow, because too many lstat() calls which are slow on NFS.

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28Sep/100

Dell SAS6/iR Windows 2003 x64 driver floppy image

When installing Windows 2003 to Dell M600 blade system windows will not recognize any hard drives. You need to load additional drivers, by pressing F6 during setup. Drivers can be found at Dell FTP site, but Dell is not providing floppy image, just drivers.

27Jul/100

Recovering deleted lvm volume

LVM is a logical volume manager for the Linux kernel; it manages disk drives and similar mass-storage devices, in particular large ones. The term "volume" refers to a disk drive or partition thereof.

Every LVM operation makes backup of lvm metadata. Metadata archive stored in directory /etc/lvm/archive/ in easily readable text files. Each operation creates own metadata backup file, with information when it was created. For example:

6Jul/100

Hardware raid in debian

To manage and monitor hardware raid, you need proper utility. Most of vendors provides raid utilities only for Redhat based linuxes. For Debian based distribution I have found very useful repository - http://hwraid.le-vert.net/wiki/DebianPackages.  You just need to know, which raid card you are using and follow provided instructions.

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5Jun/100

What makes a hard drive enterprise class?

With shrinking IT budgets you will at some point be tempted fill your RAID controllers with cheap desktop hard drives. You may also be tempted to replace your servers system drives with them as well. I'm going to give you some reasons why you should consider buying those pricey enterprise class drives instead.

10May/100

Tweak the readahead of a raid in linux

If your dealing with big RAID arrays with a linux 2.6 kernel you will need to tweak your block device readahead settings. This can double or triple your read speeds. The tweak is very easy.