Hardware vs Software RAID? That's a no-brainer. Do it in hardware, let the computer CPU work on more important things.
PE2950: Doesn't come by default with the PERC. You have to specify it when ordering. It's possible, though doubtful, that the server in question does not have the hardware RAID card in it. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edward Ned Harvey Sent: Friday, March 07, 2008 8:16 AM To: [email protected] Subject: RE: [BBLISA] Moving from RAID 0 to LVM RAID? Yeah, that's right - You did say PE 2950, and you also said raid controller only supports 0 or 1. This is almost certainly false. You have the PERC 4, 5, or 6, right? These all support Raid 5. Which is a clear choice over 0. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rick Pike Sent: Thursday, March 06, 2008 11:41 PM To: [email protected] Subject: Re: [BBLISA] Moving from RAID 0 to LVM RAID? You didn't give much detail about the hardware, but you mentioned a PE2950 which I assume is Dell Power Edge 2950. I worked with some of these last year and our standard storage configuration was 4 internal disks configured as a single RAID 5 volume using the embedded RAID controller. Actually what I had recommended was 6 smaller internal disks for the same price. The RAID 5 provided an acceptable balance between capacity, protection, and performance. We did some minimal testing to see if reconfiguring the same hardware with mirroring (was it 2 RAID 1 volumes or 1 RAID 1+0 volume?) would provide a performance boost (at the expense of capacity), but we did not notice an meaningful difference in our application. Your mileage may vary. Rick On Thu, Mar 6, 2008 at 6:58 PM, Scott R. Ehrlich <[EMAIL PROTECTED]> wrote: So I've learned a valuable RAID 0 lesson, and it fortunately was not a major catastrophy. I got lucky, and had a workable-enough backup on tape to make the user who needed some data happy. Now, from the OS side, LVM is an option. Say the RAID controller only allows hardware striping or mirroring for logical volumes, but I want to use more than two disks, and I don't want the RAID 0 problem again. 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. Insights from the OS-created RAID experience welcome. Thanks again. Scott _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa
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