[mythtv-users] RAID using two drives per PATA channel ?

[Steven Adeff]

On 7/31/06, Jens Axboe <mythtv-users at kernel.dk> wrote:
> On Mon, Jul 31 2006, Alexander Fisher wrote:
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> > Steven Adeff wrote:
> > > anyone have any insight in to whether when neglecting possible card or
> > > cable failure, would using two drives on a single PATA channel for a
> > > RAID 10 array to add two more drives lead to an overall increase in
> > > the array speed, or would the speed loss be too great for the extra
> > > drives to help any?
> >
> > According to the linux RAID HOWTO...
> > http://www.tldp.org/HOWTO/Software-RAID-HOWTO-4.html#ss4.1
> > 'It is very important, that you only use one IDE disk per IDE bus. Not
> > only would two disks ruin the performance, but the failure of a disk
> > often guarantees the failure of the bus, and therefore the failure of
> > all disks on that bus.'
> >
> > Then again, the HOWTO is somewhat out of date.  Perhaps dieing disks
> > killing the bus is just folklore?
>
> Nope, that one still holds true. If the broken drive locks up the
> bus, the other drive will be inaccessible as well.
>
> Old parallel IDE has no concept of bus release, like SCSI. Access to the
> bus is thus always serialized between the two drives, so you will see a
> performance loss as well.

I'll just wait till I can afford 4x new SATA drives then.

thanks for the info all!

-- 
Steve
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