[mythtv-users] Re:Question on software RAID

[Martin Smith]

Pete wrote:

> Ok, so sounds like build the array, then LVM on top of that. What is the
> performance penalty for that extra layer? Once I need to expand later, I
> can just add another RAID5 array into the LVM "disk"...does the LVM
> overhead go up significantly as you add more volumes to it?

I haven't measured it but in practice you're unlikely to notice the impact of
LVM.

On my storage server I have 3 x 250 GB drives in a RAID5 set split across 3 IDE
channels. The resulting /dev/md0 is then placed in an LVM volume group so space
can be allocated to filesystems at a whim. In future either a RAID 1 mirror or
another RAID 5 set can be added to increase the available space.

I see various people commenting on hardware v software RAID. My 2p on this is
that most of the lower cost cards don't offer this option and for storing TV
programmes I think software will do the job adequately.

The main thing is that you don't want more than 1 drive on the same IDE channel
as if you lose 2 disks at the same time your data is gone.

Martin