On Fri, 7 Aug 2009, Scott Meilicke wrote:
Bob, since the ZIL is used always, whether a separate device or not, won't writes to a system without a separate ZIL also be written as intelligently as with a separate ZIL?
I don't know the answer to that. Perhaps there is no current advantage. The longer the final writes can be deferred, the more opportunity there is to write the data with a better layout, or to avoid writing some data at all.
One thing I forgot to mention in my summary is that zfs is commonly used in multi-user environments where there may be many simultaneous writers. Simultaneous writers tend to naturally fragment a filesystem unless the filesystem is willing to spread the data out in advance and take a seek hit (from one file to another) for each file write. Zfs deferrment of the writes allows the data to be written more intelligently in these multi-user environments.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
