[mythtv-users] Question on software RAID
davatar at comcast.net
Mon Jan 26 12:09:21 EST 2004
> Why use Raid-5? Myth doesn't really need the I/O bandwidth
> you get from striping and you said its software Raid so you're
> going to up the CPU load. Instead you could just use the LVM
> to create a large volume set which is easier to extend.
CPU Load is is very small on modern processors, and during the low-IO that
myth does it's going to be undetectable.Put it this way, the raid-5
algorithm selection on kernel boot computes something in the neighborhood of
4000MB/s on my athlon 1300. Considering I get reads of about 100MB/s which
is mostly because of maxing out the pci bus, you get the drift.
LVM on N disks cuts your reliability to MTBF/N.
If you want a lot of space that has some reliability, and don't want to pay
_double_ the price for raid 1, raid5 is the way to go. N+1 disks needed.
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