On Mon, Jul 30, 2012 at 8:58 AM, Roy Sigurd Karlsbakk <r...@karlsbakk.net> wrote: >> > For several times now I've seen statements on this list implying >> > that a dedicated ZIL/SLOG device catching sync writes for the log, >> > also allows for more streamlined writes to the pool during normal >> > healthy TXG syncs, than is the case with the default ZIL located >> > within the pool. >> >> After reading what some others have posted, I should remind that zfs >> always has a ZIL (unless it is specifically disabled for testing). >> If it does not have a dedicated ZIL, then it uses the disks in the >> main pool to construct the ZIL. Dedicating a device to the ZIL should >> not improve the pool storage layout because the pool already had a >> ZIL. > > Also keep in mind that if you have an SLOG (ZIL on a separate device), and > then lose this SLOG (disk crash etc), you will probably lose the pool. So if > you want/need SLOG, you probably want two of them in a mirror…
That's only true on older versions of ZFS. ZFSv19 (or 20?) includes the ability to import a pool with a failed/missing log device. You lose any data that is in the log and not in the pool, but the pool is importable. -- Freddie Cash fjwc...@gmail.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
