On Dec 16, 2007 12:05 PM, Gregory K. Ruiz-Ade <[EMAIL PROTECTED]> wrote: > On Dec 15, 2007, at 11:37 PM, Bob La Quey wrote: > > > Why use hardware RAID at all if you decide to go with > > ZFS? Why not JBOD? Cheaper and more reliable (No RAID > > controller as a single point of failure for hardware > > RAID.) > > > ZFS itself uses its own algorithms for software RAID to do what you're > suggesting, anyway, so your question is somewhat contrived.
Not so much contrived as representing my original ignorance :) A better subject line: Why use hardware RAID anymore? I am doing a lot of "just in time" education on this thread. Actually I was hoping for the KPLUG crew to have already been educated on this subject so they could educate me ... but it seems for the most part the rest of the crew are about as ignorant as I am on the subject. > ZFS doesn't automatically remove RAID from the equation, it simply > moves RAID into the software level, much like the Linux MD software > RAID subsystem. > > You can use ZFS on individual devices, but the real benefits come in > when when you use multiple disks together in -- wait for it -- a RAID > configuration, using ZFS's RAIDZ (or even RAID1). > > Sure, the physical infrastructure is a JBOD, but the logical structure > is still RAID. Agreed. Good summary. Thanks. So the issue boils down to which, hardware or software, one believes is better and why. I am falling into the ZFS (let the software do it) camp. My reasoning is that this will be faster, cheaper, and just generally better in the (slightly) long run. The real progress from Moore's law is taking us toward more cpus per chip. Let's use some of that horsepower to drive ZFS and ZFS-like systems that have data integrity built into them from the get go. As Robin Harris points out it is all software. The question is where does the software run, the "main" processor or the processor in the disk controller. One argument for putting it on the "main" processor is that motherboards track gains in Moore's law much better than do disk controllers. So if you want the benefit of Moore's law do your software on the motherboard processor. See http://storagemojo.com/2006/08/15/zfs-performance-versus-hardware-raid/ Onward, BobLQ -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
