Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Tue, 12 Apr 2005, Jeff Buck wrote: > After talking to 3ware, they seem to think that part of the problem had > to do with the drives we're using.. We've got 8 250 gig western digital > drives. The problem is the particular model (according to them). Some of > the western digital drives are "workstation class" drives, and when they > see info coming in in 64K chunks, they assume it's some sort of nickle > and dime IO from a workstation, so after a 64k chunk they seek to a > random area of the disk (ala IBM Deathstar drive fix) to even out the > time spent over different areas on the disk. Next 64k chunk they seek > back, write, and seek random again. The problem being that the 3ware > raid card is splitting the writes into 64k chunks on the different > disks, causing them all to do a little dance after every 64k write. We > have a bunch of the "JD" drives.. I guess the ones that don't have this > behavior are the "SD" drives (unavailable when we started this project). Makes a lot of sense - we've actually got two seagate and two WD (JD) drives on each controller. -- Nate Carlson <natecars at real-time.com> | Phone : (952)943-8700 http://www.real-time.com | Fax : (952)943-8500