[mythtv-users] Wishlist feature for adding a hard drive

[Todd Ignasiak]

On 10/4/06, drbob <drbob at gmx.co.uk> wrote:
> Mark J. Small wrote:
> > This got me to thinking.  Wouldn't it be nice if mythtv had the option of
> > multiple storage drives/directories?  Then it could do a sort of load
> > balancing between drives.  This would be most effective if the two drives
> > were on different cables, at least for PATA.
> Someone has written a patch that does this - it's not finished yet but
> it's intended to go into the 0.21 version: see
> http://svn.mythtv.org/trac/ticket/1744
>
> However since the latest linux kernels support dynamic expansion of a
> raid5 array, I don't see much need for this for the scenarios you
> describe.See: http://scotgate.org/?p=107 and
> http://lkml.org/lkml/2006/3/20/105

You're right, RAID5 is a great way to go, but  adding multiple
independent storage units has a few advantages:

- The drives don't need to be all the same size.   WIth the ever
increasing size of hard drives, I seem to continually upgrade and have
disks of many different sizes.  I have a bunch of 120GB, a couple
250GB, a 320GB and a couple 400GB.    I can throw a 400 and 320GB disk
on my Myth backend, and have a good deal of space.

- Related to the above,  as the 'sweet spot' of disk capacity goes up,
I can just buy the new larger disk and slap it in, rather than
replacing all the disks with the new larger size, and rebuilding the
whole array (those 750GB drives are pricey now..  but they'll come
down in price soon enough).

- With single disks, I use all my storage.  I don't need have the
parity overhead, as in RAID5.   Of course, I don't get the data
protection that RAID5 offers.  But, for me TV programs don't merit
that level of protection.   Independent disks give a step up in
reliability over striped disks.. if I lose a disk, I only lose the
programs on that disk, not my entire volume.

- Even when using RAID5, your capacity is not infinite.  You might
want to use this feature to point MythTV at two RAID arrays, or NAS
units.


Just my two cents..  I think multiple storage locations for MythTV is
a fantastic improvement.   I look forward to its inclusion in a future
version.