The high order bit here is that
write();
write();
fsync();
can be executed using a single I/O latency (during the
fsync) whereas using O_*DSYNC, will require 2 I/O latency
(one for each write).
-r
Neil Perrin writes:
> As far as zfs performance is concerned, O_DSYNC and O_SYNC are equivalent.
> This is because, zfs saves all posix layer transactions (eg WRITE,
> SETATTR, RENAME...) in the log. So both meta data and data is always
> re-created if a replay is needed.
>
> Anton B. Rang wrote On 10/12/06 15:42,:
> > fsync() should theoretically be better because O_SYNC requires that each
> > write() include writing not only the data but also the inode and all
> > indirect blocks back to the disk.
> >
> >
> > This message posted from opensolaris.org
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