[CentOS] Hard disk recomendation for a software raid 5 array. Does Linux Software Raid support/interacts well with TLER enabled disks.

Alexander Georgiev alexander.georgiev at gmail.com
Fri Jul 27 12:32:39 UTC 2007


Hi people,

I am building a cheap remote rsync backup server using a software raid
5 array of 4 500GB disks. What I have available on the market is:

1. HITACHI GST Deskstar T7K500 500GB 7200rpm 16MB cache Serial ATA II-300
2. SEAGATE Barracuda 7200.10 with NCQ 500GB 7200rpm 16MB cache Serial ATA II-300
3. Western Digital 500GB SATAII RAID EDITION Caviar SE16 7200rpm 8.9ms
16MB cache

I  am tempted to use the Western Digital Raid Edition as it has 5
years of warranty. However I found out that the "Raid Edition" means
that the disk supports TLER - time limited error recovery:

http://www.excelmeridiandata.com/products/wd_raid_edition_drive.shtml

A more profound description can be found here
http://www.wdc.com/en/library/sata/2579-001098.pdf.

In summary, the error recovery time of the hard disk is reduced to 8
second. If the hard disk cannot perform the recovery it will report an
error to the RAID controller and delegate the recovery to the
controller.

As I intend to use linux software raid on Centos 5, I will not have a
RAID controller to deal with this delegated error, but two cheap  I/O
SATA controllers.

Has anybody used 'raid edition' disks with software raid?
Does anybody know how linux software raid interacts/supports these TLER disks.

Best regards
Alex



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