On Sat, 22 Mar 2003 at 12:45pm, Donghui Wen wrote
> Hi,
> We used 3ware 7500-4 as ide raid controler on a redhat advanced server
> machine.
> (kernel 2.4.9-e12, lastest 3ware driver). But we got a pretty bad write
> speed.
>
> Sequential Writes
> File Blk Num Avg
> Maximum Lat% Lat% CPU
> Identifier Size Size Thr Rate (CPU%) Latency
> Latency >2s >10s Eff
> ---------------------------- ------ ----- --- ------ ------ --------- -----
> ------ -------- -------- -----
> 2.4.9-e.12enterprise 1792 4096 1 8.99 6.920% 0.394
> 29064.03 0.00240 0.00218 130
> 2.4.9-e.12enterprise 1792 4096 2 10.55 17.61% 0.637
> 23474.59 0.00480 0.00218 60
> 2.4.9-e.12enterprise 1792 4096 4 1.94 11.22% 0.156
> 1861.13 0.00000 0.00000 17
> 2.4.9-e.12enterprise 1792 4096 8 0.83 7.171% 0.274
> 995.19 0.00000 0.00000 12
The card is capable of much better than that. Here are my numbers from a
7 disk RAID5 array (8th is a hot spare) on a 7500-8 board:
Sequential Writes
File Blk Num Avg
Maximum
Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency
Latency
>2s >10s Eff
---------------------------- ------ ----- --- ------ ------ ---------
---------
-- -------- -------- -----
2.4.18-17SGI_XFS_1.2pre3smp 4096 4096 1 49.50 20.52% 0.068
2915.
71 0.00124 0.00000 241
2.4.18-17SGI_XFS_1.2pre3smp 4096 4096 2 45.17 23.21% 0.141
7873.
45 0.00343 0.00000 195
2.4.18-17SGI_XFS_1.2pre3smp 4096 4096 4 39.98 23.29% 0.335
13338.
23 0.00887 0.00010 172
2.4.18-17SGI_XFS_1.2pre3smp 4096 4096 8 39.23 24.30% 0.631
7887.
96 0.01535 0.00000 161
Obviously I've got more spindles, but your speeds shouldn't be *that* bad.
Some things to check:
1) You said latest drivers, but make sure that you upgraded everything --
a driver set from 3ware is driver+firmware+3dm. Specifically, make sure
your firmware is up to date with your driver.
2) Make sure that your kernel supports HIGHIO. I don't know if that
enterprise kernel does (do you need to run it?), but it makes a *big*
difference. The latest 3ware drivers support HIGHIO, but the kernel needs
to as well.
3) Make sure your drives are listed as compatible.
4) Try a different FS. The numbers above are with XFS -- with ext3 I was
getting write speeds of only half that (at best).
Good luck.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
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