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
Richard Tector 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.You looked in the controller's BIOS, not motherboard's, right? There should be at least a "write through" vs "write back" switch... If you don't have a battery for the SAS controller, get one.> Has anyone else experienced this issue?No, but can you post the relevant bits for the controller from dmesg? -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 250 bytes Desc: OpenPGP digital signature Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20070327/67bbd453/signature.pgp
It's been seen before but the fix isn't know yet. On 3/27/07, Richard Tector <richardtector@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 > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >