Andrew Elwell wrote:
> We've just got a ~48TB storage box here at Glasgow. - 2*3ware cards with
> 24*1T disks on each.
>
> Painfully slow out of the box (it may be verifying just now - tw_cli
> unresponsive) but I discovered this snippet on the 3ware website
>
> http://www.3ware.com/kb/article.aspx?id=11050
>
> gives some tuing tips. Anyone else have some to share?
I did some benchmarking on a 16drive 3ware setup:
http://map2.ph.liv.ac.uk/2007/04/13/raid5-performance-tweaking/
Mostly covers the 3ware tips and tuning xfs.
The performance gains are geared towards small numbers of large files,
lots of small files will want the simultaneous requests and read-ahead
reduced.
Out of the box the array should be fine unless it's initialising in the
background, but tw_cli should still be mostly responsive no matter what.
If you use the 3DM2 web interface (might be in tw_cli as well but I can
never remember where, and default password is 3ware) in Controller
configuration for each unit you can specify a performance level
Performance, Balanced or Protection, which boils down to how paranoid
you are about power loss during writes and whether you have a battery
backup unit. Performance does make a big difference on writes but only
recommended if you have a BBU on the card and UPS on the server.
You can also specify the rate of initialisation/rebuild and verifying
compared to normal io operations. I tend to set the rebuild as highest
priority (want that sucker redundant again asap) and verifies as low
priority (an extra hour or two is unlikely to change whether the array
is broken or not right now).
John
--
Dr John Bland, Systems Administrator
Room 210, Oliver Lodge
Particle Physics Group, University of Liverpool
Mail: [log in to unmask]
Tel : 0151 794 3396
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