On Thu, Jun 02, 2011 at 11:19:25AM -0700, Josh Simon wrote: > I don't believe this to be the reason since there are other SATA > (single-port) SSD drives listed as approved in that same document. > > Upon further research I found some interesting links that may point to a > potentially different reason for not using the Intel X25-E with a SAS > Expander: > > http://gdamore.blogspot.com/2010/08/why-sas-sata-is-not-such-great-idea.html > > "Update: At a significant account, I can say that we (meaning Nexenta) > have verified that SAS/SATA expanders combined with high loads of ZFS > activity have proven conclusively to be highly toxic. So, if you're > designing an enterprise storage solution, please consider using SAS all > the way to the disk drives, and just skip those cheaper SATA options. > You may think SATA looks like a bargain, but when your array goes > offline during ZFS scrub or resilver operations because the expander is > choking on cache sync commands, you'll really wish you had spent the > extra cash up front. Really." > > and > > http://gdamore.blogspot.com/2010/12/update-on-sata-expanders.html > > This sounds like it will affect a lot of people since so many are using > SATA SSD for their log devices connected to SAS expanders. > > Thanks, > > Josh Simon >
Yup; reset storms affected us as well (we were using the X-25 series for ZIL/L2ARC). Only the ZIL drives were impacted, but it was a large impact :) Our solution was to move the SSD's off of the expander and remount internally attached via one of the LSI SAS ports directly (we also had problems with running the drives directly off the on-board SATA ports on our SuperMicro motherboards -- occasionally the entire zpool would freeze up). Ray > > On 06/02/2011 01:25 PM, Jim Klimov wrote: > > 2011-06-02 18:40, Josh Simon пишет: > >> I was just doing some storage research and came across this > >> http://www.nexenta.com/corp/images/stories/pdfs/hardware-supported.pdf. In > >> that document for Nexenta (an opensolaris variant) it states that you > >> should not use Intel X25-E SSDSA2SH032G1 SSD with a SAS Expander. Can > >> anyone tell me why? > >> > >> This seems to be a very common drive people deploy in ZFS pools. > > > > I believe one reason is that these are single-port devices - and as such > > do not support failover to another SAS path. > > > > > > //Jim _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
