Dell SAS5 Performance Issue

[Matthew Jacob]

not at the momeny- it's really that I won't have time until april

On 3/27/07, Richard Tector <richardtector at thekeelecentre.com> wrote:
> Matthew Jacob wrote:
> > It's been seen before but the fix isn't know yet.
> >
> > On 3/27/07, Richard Tector <richardtector at thekeelecentre.com> wrote:
> >> I'm suffering from very slow write performance on a Dell PowerEdge 860
> >> with the SAS5/IR controller (mpt driver) running either 6.2-RELEASE or
> >> 6.2-STABLE with sources from yesterday. The controller hosts 2 Western
> >> Digital 320GB SATA disks in a RAID1 configuration.
> >> Reads approach 65MB/s however writes appear extremely slow, in the
> >> region of 6-7MB/s with a dd and a blocksize of 1MB all the way down to
> >> about 300KB/s while extracting a ports snapshot.
> >>
> >> It was suggested to me that perhaps write caching has been disabled on
> >> the controller however no options exist within the BIOS configuration to
> >> view/adjust *any* caching options.
> >>
> >> Has anyone else experienced this issue? If so how did they resolve it?
> >> Also, is there any way to toggle the caching settings from FreeBSD?
> >>
> >> Regards,
> >>
> >> Richard Tector
> >> _______________________________________________
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> >>
> Thank you for the quick reply.
> Is there any information I could obtain that would be of use to you in
> tracking this one down?
>
> Regards,
>
> Richard
>