Bob Friesenhahn wrote: > On Fri, 16 May 2008, James C. McPherson wrote: >>> 3) I've read that it's best practice to create the RAID set utilizing >>> Hardware RAID utilities vice using ZFS raidz. Any wisdom on this? >> You've got a whacking great cache in the ST2540, so you might as >> well make use of it. > > Exporting each disk as a LUN for use by ZFS does not cause the 2540 to > disable its cache. In fact, it is clear that this cache is quite > valuable to ZFS write performance when NFS is involved. I am able to > obtain 90MB/second NFS write performance from a single NFS client and > using the 2540. > > Due to the inherent design of ZFS, it is not necessary for RAID writes > to be synchronized as they must be for traditional mirroring or RAID5. > If there is a power loss or crash, ZFS will discover where it left > off, and bring all redundant copies to a coherent state. The 2540's > cache will help protect against losing data if there is a power fail.
Hi Bob, You've made an assumption about what I wrote. That assumption is incorrect. Kenny, in addition, did not say that he was or was not going to do what you suggested, and I suggested to him that he go and look into the ZFS Best Practices wiki to get some ideas. I'm very, very well aware of the design and behaviour of ZFS, I have been using it since the build it was first integrated. I am also quite well aware of the design and behaviour of the raid engine in the ST2530. Please re-read my email to Kenny, and don't put in words that I didn't write. James C. McPherson -- Senior Kernel Software Engineer, Solaris Sun Microsystems http://blogs.sun.com/jmcp http://www.jmcp.homeunix.com/blog _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
