Hi Roch,

That sounds like a most excellent resolution to me. :-) I believe
Engenio devices support SBC-2. It seems to me making intelligent
decisions for end-users is generally a good policy.

Best Regards,
Jason

On 12/19/06, Roch - PAE <[EMAIL PROTECTED]> wrote:


Jason J. W. Williams writes:
 > Hi Jeremy,
 >
 > It would be nice if you could tell ZFS to turn off fsync() for ZIL
 > writes on a per-zpool basis. That being said, I'm not sure there's a
 > consensus on that...and I'm sure not smart enough to be a ZFS
 > contributor. :-)
 >
 > The behavior is a reality we had to deal with and workaround, so I
 > posted the instructions to hopefully help others in a similar boat.
 >
 > I think this is a valuable discussion point though...at least for us. :-)
 >
 > Best Regards,
 > Jason
 >

To Summarize:

Today, ZFS sends a ioctl to  the storage that says flush the
write  cache, while what it really  wants is, make sure data
is on stable storage.  The  Storage should then flush or not
the cache  depending on if   it is considered stable  or not
(only the storage knows that).

Soon  ZFS (more precisely SD)  will be sending a 'qualified'
ioctl to clarify the requested behavior.

In    parallel, Storage vendor    shall be implementing that
qualified  ioctl.   ZFS  Customers  of third   party storage
probably have more influence to get those vendors to support
the qualified behavior.

http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6462690

With  SD fixed and Storage  vendor support, there will be no
more need to tune anything.

-r



 > On 12/15/06, Jeremy Teo <[EMAIL PROTECTED]> wrote:
 > > > The instructions will tell you how to configure the array to ignore
 > > > SCSI cache flushes/syncs on Engenio arrays. If anyone has additional
 > > > instructions for other arrays, please let me know and I'll be happy to
 > > > add them!
 > >
 > > Wouldn't it be more appropriate to allow the administrator to disable
 > > ZFS from issuing the write cache enable command during a commit?
 > > (assuming expensive high end battery backed cache etc etc)
 > > --
 > > Regards,
 > > Jeremy
 > >
 > _______________________________________________
 > zfs-discuss mailing list
 > zfs-discuss@opensolaris.org
 > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss


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