[stgt] Write-cache in tgtd during a target-host crash

FUJITA Tomonori fujita.tomonori at lab.ntt.co.jp
Fri Apr 23 03:26:22 CEST 2010


On Wed, 21 Apr 2010 19:51:49 +1000
ronnie sahlberg <ronniesahlberg at gmail.com> wrote:

> It would also be very useful to tell tgtd to use either or both of
> O_SYNC/O_DIRECT for all i/o depending on the semantics of the
> filesystem used to hos the lun files.

tgt opens a file with just O_LARGEFILE. If you enable the writeback
cache (on the target or initiator), tgt issues write and
sync_file_range system calls.

WCE bit can be changed at runtime, so I'm not sure using O_SYNC for
the writeback cache.

About O_DIRECT, what's the advantage of using O_DIRECT?

Note that you configure tgt to use AIO, tgts uses
O_LARGEFILE|O_DIRECT.
--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html



More information about the stgt mailing list