[mythtv-users] FC4 software raid (LVM)

[Glen Johnson]

> 
> Now create a LogicalVolume in the VolumeGroup:
> lvcreate -i 4 -l 152600
> 
> The -l 152600 sets the size of the volume as measured in
> PhysicalExtents.
> The -i 4 means create a stripe set. I like to use a stripe set because
> it divides work across all the drives evenly. So if you're writing a 1
> gigabyte episode of Friends, each drive gets 250 megabytes. Little
> pieces are written to each drive in turn. If you don't use a stripe
> set, then drive sdb fills first, then drive sdc, etc. This can lead to
> sdb sitting there with your archives of Alias, while sde is busily
> recording and deleting whatever you're watching later. One drawback is
> that if a drive in a stripe set goes bad, everything is lost. The
> alternative is a RAID array, usually RAID5. However, you loose a
> certain percentage of your space to the redundant nature of the array.
> I think this is about 1 drives worth of space, but am not positive. In
> the case of 4 drives, you would loose 25%.

Thanks for the very detailed reply.  Way more info than I expected but
greatly appreciated.
After reading the man pages on pvcreate, lvcreate and lvm, I'm still not
sure what parm to use to change from s plain stripe set to a RAID5 set.
That's what I really want as I've had one drive fail within the last 3
months.
Thanks again.
Glen.