On Apr 22, 2010, at 8:08 PM, Ray Van Dolson <rayvd at bludgeon.org> wrote: > On Thu, Apr 22, 2010 at 03:57:01PM -0700, nate wrote: >> John R Pierce wrote: >>> Ray Van Dolson wrote: >>>>> I think what you want is a proper storage array with mirrored >>>>> write >>>>> cache. >>>>> >>>> >>>> Which is what we have with ZFS + SSD-based ZIL for far less money >>>> than >>>> a NetApp. >>>> >>> >>> not unless you have a pair of them configured as an active/standby >>> HA >>> cluster, sharing dual port disk storage, and some how (magic?) >>> mirroring >>> the cache pool so that if the active storage controller/server >>> fails, >>> the standby can take over wthout losing a single write. >>> >> >> OT too but really thought this was a good post/thread on ZFS >> >> http://www.mail-archive.com/zfs-discuss@opensolaris.org/msg18898.html >> >> "ZFS is designed for high *reliability*" >> [..] >> "You want something completely different. You expect it to deliver >> *availability*. >> >> And availability is something ZFS doesn't promise. It simply can't >> deliver this." > > Yep... and something you of course know going in. > > Don't want to get off on a tangent on that -- am still interested what > type of solutions in the Linux world are out there that can > approximate > what an SSD based ZIL does for ZFS. > > Kent Overstreet (from lkml) mentioned that his bcache patch is > intented > to do something very similar. > > So I guess that's my answer -- it's not here yet, so sounds like the > controller is the only way to achieve this currently. How about locating XFS journal on SSDs and using HW RAID controller with big NVRAM cache. That should be a lot faster than ZFS with SSD ZIL. NFS should always be 'sync' if performance isn't good, then your storage isn't good. -Ross