[CentOS] 3Ware 9550SX and latency/system responsiveness

[Simon Banton]

At 15:43 +0200 14/9/07, Sebastian Walter wrote:
>Simon Banton wrote:
>  > No, I haven't. This is 3ware hardware RAID-1 on two disks with a
>>  single LVM ext3 / partition - I'm afraid I don't know how to go about
>>  discovering the chunk size to plug into Ross's calcs.
>
>You can see the chunk size either in the raid's BIOS tool (Alt-3 at
>startup) or, if installed, in the 3dm CLI (defaults to 64k, I think).

Hmmm, from what I can see in the tw_cli documentation, stripe size 
(and hence, presumably, chunk size) doesn't apply to RAID 1.

(apologies is the formatting goes awry):

Stripe consists of the logical unit stripe size to be used. The 
following table illustrates the supported and applicable stripes on 
unit types and controller models. Stripe size units are in K (kilo 
bytes).

      Model | Raid0   | Raid1  | Raid5  | Raid10  | JBOD | Spare | 
Raid50 | Single |
 
------+---------+--------+--------+---------+------+-------+--------+--------+
      9K    |   16    |   N/A  |   16   |   16    | N/A  |  N/A  | 
16   |   N/A  |
            |   64    |        |   64   |   64    |      |       | 
64   |        |
            |   256   |        |   256  |   256   |      |       | 
256  |        |
 
------+---------+--------+--------+---------+------+-------+--------+--------+

I'm focused now on swapping the card for a fresh one to see if it 
makes any difference, as per Ross's suggestion.

S.