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Scott R. Ehrlich wrote: > When I get a replacement disk and build the system from the ground up > again, I could, conceivably, use hardware RAID 1 for the OS on two > disks, and CentOS 5 64-bit's LVM for software RAID 5 (or maybe 1+0 if > available) on the remaining for 4 disks, maybe 3 disks as active and the > 4th as a hot spare? > > I've never had much faith in software raid, since it is not > hardware-based, and there would be a performance hit, but in this case, > it could be an option. From a purely logical standpoint (I don't have the inclination to do actual performance tests myself, since I don't have any RAID hardware, and the software works fine for me), there's not much that hardware will gain you over software when doing RAID-1. RAID-1 is all about bandwidth to the drives, so as long as you have separate buses that can write to more than one disk in parallel, that probably dwarfs any other issues. With RAID-5 the story is a little different, since the parity calculation would actually chew up some CPU cycles. There, hardware-assist would probably make a noticeable difference. Personally, I don't see the attraction to RAID-5; it's more complexity for very marginal cost benefit (which is probably negated completely by the cost of the RAID controller...) I'd be curious to see some performance tests of a hardware RAID controller vs. a couple SATA drives using SW RAID, for both the 1 and 5 flavors. Finally, one last point in favor of SW RAID: a bug in the implementation can be fixed easily. If your RAID-controller has a bug, you're fsck'd. Matt -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. _______________________________________________ Discuss mailing list [hidden email] http://lists.blu.org/mailman/listinfo/discuss
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