Re: Very slow HP 8 Internal Port SAS HBA with RAID 0, 1 on Hot Plug SAS/SATA Models (LSI SAS1068 - mpt)

From: Jeremy Chadwick <koitsu_at_FreeBSD.org>
Date: Thu, 18 Oct 2007 01:58:12 -0700
On Thu, Oct 18, 2007 at 09:20:32AM +0100, Richard Tector wrote:
> Stefan Lambrev wrote:
>> Enabling write cache really helps, so now I have to find a battery backup 
>> unit for the controller (if  it supports it).
>> Anyway here are the results of bonnie++ :
>> Version 1.93c       ------Sequential Output------ --Sequential Input- 
>> --Random-
>> Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- 
>> --Seeks--
>> Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  
>> /sec %CP
>> netguard.com 16G   416  99 63957  15 26411   8   702  99 70399  13 192.2   
>> 5
>> Latency             21185us     462ms     785ms   22855us     134ms     
>> 139ms
>> Version 1.93c       ------Sequential Create------ --------Random 
>> Create--------
>> netguard.com  -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
>> files:max:min        /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  
>> /sec %CP
>> 256:65536:65536/16   865  13   897   9 30908  60   858  13    88   2  6251 
>>  48
>> Latency              1082ms     136ms     357ms    1678ms    3044ms    
>> 1065ms
>> 1.93c,1.93c,netguard..com,1,1192619536,16G,,416,99,63957,15,26411,8,702,99,70399,13,192.2,5,256,65536,65536,,16,865,13,897,9,30908,60,858,13,88,2,6251,48,21185us,462ms,785ms,22855us,134ms,139ms,1082ms,136ms,357ms,1678ms,3044ms,1065ms 
>> But isn't 70MB/s sequential read little slow for raid 1 with 2x500GB SATA 
>> II HDDs?
>
> 70MB/s from desktop drives is pretty respectabloe, IMHO.

In a RAID 1 configuration, I would say 70MByte/sec read is more than
decent.  That's about what I get from an individual drive on a built-in
nVidia nForce 4 SATAII controller.  Here's a sequential read from a disk
on that controller, using dd and gstat; sometimes it hits 78MB.

ad10: 476940MB <Seagate ST3500630AS 3.AAE> at ata5-master SATA300

 L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name
    1    571    571  72850    1.4      0      0    0.0   82.0| ad10

You might also want to verify that the disks are actually running
at SATA300 speeds (which won't necessarily gain you a lot over SATA150,
but worth turning on assuming it's compatible with your controller).
Seagate drives, for example, have a little jumper on them that limits
the interface to SATA150; remove it.

-- 
| Jeremy Chadwick                                    jdc at parodius.com |
| Parodius Networking                           http://www.parodius.com/ |
| UNIX Systems Administrator                      Mountain View, CA, USA |
| Making life hard for others since 1977.                  PGP: 4BD6C0CB |
Received on Thu Oct 18 2007 - 06:58:12 UTC

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