Most ZFS improvements should be available through patches. Some may require moving to a future update (for instance, ZFS booting, which may have other implications throughout the system).
On most systems, you won’t see a lot of difference between hardware or software mirroring. The benefit of software mirroring is primarily that you don’t depend on a controller. ZFS gives the additional benefit that not only a failed disk block, but one which was written incorrectly, can be detected and recovered from the alternate side of the mirror. The benefit of hardware mirroring is twofold. First, the “dirty map” can be maintained in fast hardware (e.g. NVRAM), which can reduce the amount of time that it takes to rebuild the mirror at startup and may slightly increase the speed of random writes. (ZFS uses a different technique to maintain consistency and does not need to rebuild its mirror after a crash, unlike SVM.) Second, you only move the data once across the host bus and disk controller, instead of twice, which on a heavily loaded system can increase your I/O throughput. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
