[mythtv-users] Linux software raid question

Graham Wood mythtv-users at spam.dragonhold.org
Wed Jun 11 13:28:18 UTC 2008

On Wed, Jun 11, 2008 at 09:15:30AM -0400, Carl L. Gilbert wrote:
> I know, but what happens when a drive fails.  I switched to hardware
> RAID not because of runtime performance, but because of ease of recovery
> in failure.  It does not matter if the partitions are mirrored.  Either
> you have the bootloader in the MBR, or on the boot sector of an
> individual partition. The BIOS will only point to a single bootloader
> and if the drive with that fails, you must go into BIOS and change it.
Not always.  My machine boots off the first SATA drive.  If it breaks, it'll move onto the 
next one, etc.

Since the system will boot of the subsequent disks, and grub is setup to boot off the disk 
that has the boot loader, it'll work perfectly.  Not as "clean" as a real HW raid, but 
nowhere near the cost either.

> So your saying SW RAID resyncs faster than HW RAID?
Certainly possible.  The HW RAID controller is normally a custom chip, but the data 
throughput of it is less than the throughput of the CPU.  There are quite a few surveys out 
there about performance and rebuild speed... If you're not heavily loading the CPU then 
software RAID is often faster, yes.

YMMV, I am not the world, shit happens, etc, etc.

There's no "best" answer that covers everything.  For ease of use, HW Raid is still better 
for most people.  However, the cost differential is (again for most people) normally not 
worth the effort.


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