Date: Wed, 12 May 2004 14:37:31 -0400 From: Don Bowman <don@sandvine.com> To: 'Jens Schweikhardt' <schweikh@schweikhardt.net>, Scott Long <scottl@freebsd.org> Cc: freebsd-scsi@freebsd.org Subject: RE: 2120S Stripe - abysmal performance Message-ID: <FE045D4D9F7AED4CBFF1B3B813C85337051D8C15@mail.sandvine.com>
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From: Jens Schweikhardt [mailto:schweikh@schweikhardt.net]
>
> On Wed, May 12, 2004 at 11:48:06AM -0600, Scott Long wrote:
> ...
> # I can't remember how the 2100 BIOS works, I'll have to take a look.
> # I thought that it was an attribute that was set when the array is
> # created.
>
> Yes, and once its set at array creation time it apparently can not be
> changed. I deleted the array and created it anew to disable read
> caching. This did not yield any perfomance gain by itself. After I
> changed the cables I now have 79MB/s (formerly only 29MB/s, a single
> disk has a sustained read speed of 71MB/s at the outer sectors). Next
> thing will be going back from forced U160 mode to U320. I'll
> report the
> results, so watch this space :-)
>
With aaccli, one can see the values of the cache:
AAC0> container show cache 0
Executing: container show cache 0
Global Container Read Cache Size : 0
Global Container Write Cache Size : 16203776
Read Cache Setting : DISABLE
Write Cache Setting : ENABLE ALWAYS
Write Cache Status : Active, not protected, battery not present
and set it:
AAC0> ? container set cache
Executing: container set cache help
container set cache - Sets caching parameters for a container. Useful only
if
a native operating system's file system resides on the
container.
FORMAT - container set cache {container}
/read_cache_enable - If you set this switch to TRUE, the command enables
the read cache for the specified container.
/unprotected - Specifies whether to set the container's write cache to
disable, enable when protected, or enable always. You use
this switch in conjunction with the /unprotected switch
to
accomplish the desired setting. See the CLI Reference
Guide for more information.
/write_cache_enable - Specifies whether to set the container's write
cache
to disable, enable when protected, or enable
always. You use this switch in conjunction with
the
/unprotected switch to accomplish the desired
setting. See the CLI Reference Guide for more
information.
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