[Beowulf] Re: Large raid rebuild times
landman at scalableinformatics.com
Fri Nov 20 09:32:08 EST 2009
Robert Sandilands wrote:
> I am currently rebuilding a 28 x 1 TB RAID 5 volume that is based on the
> SurfRAID TRITON 16S3 with a JBOD unit. It is 16.6% complete after 2 1/2
> I am rebuilding before copying the data and returning all the Seagate 1
> TB drives. Replacing it with Hitachi 2 TB drives and RAID 6.
> The combination of a large number of drives in RAID 5 and/or Seagate 1
> TB drives is not to be recommended.
Actually, you shouldn't be using RAID5 any more. The bit error rates
suggest that you will in all likelihood, hit an uncorrectable error
within a very small number of rebuilds, and lose data.
This is fairly well known at this point, so I have to admit surprise to
hear of anyone using 20+ drives of TB size in a RAID5.
On Seagate, YMMV, they have been rock solid for us and our customers
(thousands shipped, scales of PBs of storage). Failure rates somewhat
above their statistical estimates, very much in line with what Google
indicates they have observed with their drives.
We haven't used Hitachi very much in our units, so I can't comment much
on their quality/failure rate.
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics, Inc.
email: landman at scalableinformatics.com
web : http://scalableinformatics.com
phone: +1 734 786 8423 x121
fax : +1 866 888 3112
cell : +1 734 612 4615
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