> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of v > > For synchronous write, and if io is small, will the whole io be place > on zil? or just the pointer be save into zil? what about large size io?
This one doesn't have a really clear answer. The best answer, I believe, is here: http://opensolaris.org/jive/thread.jspa?messageID=486531&tstart=0 Scroll down to about 1/3. There is a message from perrin, as follows: > If there's a slog then the data, regardless of size, gets written to > the > slog. > > If there's no slog and if the data size is greater than > zfs_immediate_write_sz/zvol_immediate_write_sz > (both default to 32K) then the data is written as a block into the pool > and the block pointer > written into the log record. This is the WR_INDIRECT write type. > > So Matt and Roy are both correct. > > But wait, there's more complexity!: > > If logbias=throughput is set we always use WR_INDIRECT. > > If we just wrote more than 1MB for a single zil commit and there's more > than 2MB waiting > then we start using the main pool. > > Clear as mud? This is likely to change again... _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
