Linked by Thom Holwerda on Fri 18th Sep 2009 13:40 UTC, submitted by Robert Escue
Hardware, Embedded Systems This is an article which discusses the increase in storage capacity while performance and hard error rates have not improved significantly in years, and what this means for protecting data in large storage systems. "The concept of parity-based RAID (levels 3, 5 and 6) is now pretty old in technological terms, and the technology's limitations will become pretty clear in the not-too-distant future " and are probably obvious to some users already. In my opinion, RAID-6 is a reliability Band Aid for RAID-5, and going from one parity drive to two is simply delaying the inevitable."
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zfs and RAIDZ
by fridder on Fri 18th Sep 2009 15:37 UTC
fridder
Member since:
2007-11-03

I am a little sleepy, so I may be looking at this wrong, but would RAIDZ, with the whole checksumming bit and all that, mitigate some the issues here? I also wonder what is the comparable time to rebuild a raidz volume to what the author presented here.

Reply Score: 2

RE: zfs and RAIDZ
by Robert Escue on Fri 18th Sep 2009 16:02 in reply to "zfs and RAIDZ"
Robert Escue Member since:
2005-07-08

Adam Leventhal explains it much better than I can:

http://blogs.sun.com/ahl/entry/double_parity_raid_z

ZFS definitely helps, so does a good backup strategy. You are only as safe as your last successful restore.

Reply Parent Score: 3

RE: zfs and RAIDZ
by christian on Sat 19th Sep 2009 10:27 in reply to "zfs and RAIDZ"
christian Member since:
2005-07-06

I also wonder what is the comparable time to rebuild a raidz volume to what the author presented here.


The time to rebuild a RAIDz array depends not on the array size, but on the used data size of the array. RAIDz only rebuilds the blocks referenced by the higher levels of the filesystem stack, which is possible because it is so integrated with the higher level fileystem.

So in answer to your question, it depends.

Reply Parent Score: 1