On Apr 6, 2012, at 4:58 PM, Marion Hakanson wrote: > a...@blackandcode.com said: >> I'm spec'ing out a Thumper-esque solution and having trouble finding my >> favorite Hitachi Ultrastar 2TB drives at a reasonable post-flood price. The >> Seagate Constellations seem pretty reasonable given the market circumstances >> but I don't have any experience with them. Anybody using these in their ZFS >> systems and have you had good luck? > > We have a lot of 2TB and 3TB Seagates here, they work fine. Most of > ours are the Nearline-SAS variety, in Dell MD1200 enclosures, used on > Windows & Linux behind PERC H800 RAID cards, and on Solaris-10 and > OpenIndiana behind LSI SAS HBA's. We do have one new server with a > pile of 2TB SATA Seagate's as well, so far working fine. > > The only caveat I've found is that the Nearline SAS Seagates go really > slow with the Solaris default multipath load-balancing setting > (round-robin). Set it to "none" or some large block value and they go > fast. This issue doesn't appear when used with the PERC H800's.
We are starting to see a number of SAS HDDs that prefer logical-block to round-robin. I see this with late model Seagate and Toshiba HDDs. There is another, similar issue with recognition of multipathing by the scsi_vhci driver. Both of these are being tracked as https://www.illumos.org/issues/644 and there is an alternate scsi_vhci.conf file posted in that bugid. We're considering making logical-block the default (as in above bugid) and we have not discovered a reason to keep round-robin. If you know of any reason why round-robin is useful, please add to the bugid. -- richard -- ZFS Performance and Training richard.ell...@richardelling.com +1-760-896-4422
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