hiya
anyone using the 144GB drives?
currently we have DS14s filled with 36GB drives. these are used in a production environment, so of course we need maximum uptime. we're considering getting more DS14s filled with either 72GB or 144GB drives. we want the most bang for the buck, but i have concerns about the 144GB drives. anyone out there have any experience with them?
are the reconstruct times for a 144GB disk proportionally prohibitive when compared to 72GB and 36GB drives? how long does it take to reconstruct a failed 144GB drive on a hot spare compared to 72GB and 36GB disks, under consistent filer workload and raid reconstruct speed?
are there performance issues to consider if we were to go with 144GB rather than 72GB?
any other pros and cons?
thanks in advance, kallen
We have 760s, 840s, and 880s with 72G DS14s. We have seen a higher failure rate with the 72s than with the 36s but not anything that has been a real problem (our SLA includes 4 hour turnaround on replacement drives). The 72G drives take anywhere from 3-6 hours to complete depending on how busy the filer is. We use the recommended 8 drive raidset sizes on filers with 72G drives. I know nothing about 144s but I thought I would share 72G info.
We are looking at purchasing DS14 - 144s so I am curious what those who have them say about their performance/reliability. C-
On Mon, Feb 03, 2003 at 06:52:31PM -0800, kallen@collab.net wrote:
hiya
anyone using the 144GB drives?
currently we have DS14s filled with 36GB drives. these are used in a production environment, so of course we need maximum uptime. we're considering getting more DS14s filled with either 72GB or 144GB drives. we want the most bang for the buck, but i have concerns about the 144GB drives. anyone out there have any experience with them?
are the reconstruct times for a 144GB disk proportionally prohibitive when compared to 72GB and 36GB drives? how long does it take to reconstruct a failed 144GB drive on a hot spare compared to 72GB and 36GB disks, under consistent filer workload and raid reconstruct speed?
are there performance issues to consider if we were to go with 144GB rather than 72GB?
any other pros and cons?
thanks in advance, kallen
Here are the results of the tests I ran to check the raid reconstruct speed of a node in an 880c with 72GB drives. The filer was not being used, so the only load was the reconstruct. This is just the base time to reconstruct. One can find a multiplier that can be used to determine the reconstruct speed with the avg load on their filers....although I don't know how easy that would be to find.
RAID set size Elapsed (time to reconstruct) 2 29:43.70 (29 min, 43.70 sec) 3 39:59.72 4 51:58.87 5 1:04:17.90 6 1:16:40.76 7 1:29:39.19 8 1:43:01.75 9 1:56:02.55 10 2:09:19.00 11 2:22:39.12
As you can see the time to reconstruct appears to go up by about 11-14 minutes when adding an additional disk. More info on tests: cluster 880 all disks were on the same shelf: DS14 all disks were zero'ed before the reconstruct raid.reconstruct.perf_impact medium raid.resync.perf_impact medium
procedure repeated for each raid size: -priv set diag -setflag raid_enable_prezeroing 1 after done all disks zero'ed -setflag raid_enable_prezeroing 0 -vol create vol1 -r 14 11 after volume is created -disk fail (parity disk in vol1) times taken -vol offline vol1 -vol destroy vol1 -disk unfail (disk failed)
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Chris Blackmor -
Jeff Burton -
kallen＠collab.net