Hello Michael,

We have a RAID6 array with 16 U320 SCSI disks, 10000 RPM, running on SL 4.2,
it works fine.
And it is fast: Write: 175MB/s Read: 210MB/s (results from bonnie test)

For my opinion, it is always a good idea to run RAID6 instead of RAID5 with
more than 10 disks.

There are no raidtools in SL 4.2, use mdadm instead.

I created this RAID6 array with the following statement:
mdadm --create /dev/md2 --verbose --chunk=64 --level=raid6 --raid-devices=16
/dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1
/dev/sdh1 /dev/sdi1 /dev/sdj1 /dev/sdk1 /dev/sdl1 /dev/sdm1 /dev/sdn1
/dev/sdo1 /dev/sdp1

Regards

Peter

 	Peter Stauffert
	Boehringer Ingelheim Pharma GmbH & Co. KG
		Department of Lead Discovery
		Computational Chemistry
		


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Gesendet: Dienstag, 14. März 2006 20:35
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Betreff: Software RAID 6 in SL 4.2?


Greetings.

I happened to read the following article as I was in the process of 
configuring a new file server:

     https://www.hepix.org/documents/HEPiX_GDB_STF_v1.0.0.0-1.pdf

Among other things, the article suggests that using SATA II drives in a 
RAID 6 configuration is probably a reasonable approach for a file server.

I'd like to configure a RAID 6 array in SOFTWARE on this system, which 
will be running SL 4.2.  (This will be a fast, dual-processor system, 
with plenty of cycles to dedicate to the checksumming process, and the 
software approach uses tools that are widely used and open-source, 
versus whatever voodoo the vendors include in their RAID cards.)

I contacted a systems vendor about this.  The sales guy told me that he 
doesn't think software RAID 6 is possible in Redhat (or similar).

I've found some information on the web that suggests that software RAID 
6 was experimental in Dec. 2003.  That COULD have gotten worked out in 
the interim, but the documentation for RHEL 4 shows only RAID 0, 1, and 
5 as options for software RAID.

It would appear that I'll have to go with hardware RAID.  If you have 
any better information about software RAID 6 in SL, please let me know.

Thanks.

					- Mike
-- 
Michael Hannon            mailto:[log in to unmask]
Dept. of Physics          530.752.4966
University of California  530.752.4717 FAX
Davis, CA 95616-8677