[CentOS] Re: A question about RAID and partitions

Tue May 22 23:53:32 UTC 2007
Scott Silva <ssilva at sgvwater.com>

Miguel Medalha spake the following on 5/22/2007 4:46 PM:
>> You could always combine software raid and LVM.
>> Create a RAID1 device using Software RAID.
>> Then set up LVM with the apropriate LVM logical volumes under /dev/md0
>> or whatever.
> Ok, I'll accept that. My initial question remains, albeit under a
> different form:
> - Create a single RAID 1 device with both entire disks and then put LVM
> logical volumes on top
> - Create several RAID devices, one for each mount point (md0, md1, md2
> and so forth)
> Which one would be better under the aspects of performance (CPU
> utilization, disk
> transfer rate, etc), data security and ability to recover from a disk
> crash?
> Does LVM bring a performance penalty?
I don't think LVM brings any penalty. But with raid mirrors on separate
partitions, you could recover data with something as simple as a Knoppix disk.
You can mount each partition and get to the data. If the LVM metadata becomes
corrupt (less likely with LVM2, but it can happen) you have a harder time
getting data back. The plus with LVM is snapshots, which give very reliable


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