> There are also the speed enhancement provided by a HW > raid array, and > usually RAS too, compared to a native disk drive but > the numbers on > that are still coming in and being analyzed. (See > previous threads.)
Speed enhancements? What is the baseline of comparison? Hardware RAIDs can be banalized to two features: cache which does data reordering for optimal disk writes and parity calculation which is being offloaded off of the server's CPU. But HW calculations still take time, and the in-between, battery backed cache serves to replace the individual disk caches, because of the traditional file system approach which had to have some assurance that the data made it to disk in one way or another. With ZFS however the in-between cache is obsolete, as individual disk caches can be used directly. I also openly question whether even the dedicated RAID HW is faster than the newest CPUs in modern servers. Unless there is something that I'm missing, I fail to see the benefit of a HW RAID in tandem with ZFS. In my view, this holds especially true when one gets into SAN storage like SE6920, EMC and Hitachi products. Furthermore, need I remind of the buggy SE6920 firmware? I don't trust it as far as I can throw it. Or, lets put it this way: I trust Mr. Bonwick a whole lot more than some firmware writers. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
