[mythtv-users] Storage Solution: Can ya help a brother out?

[Glen Dragon]

On Mon, Nov 24, 2008 at 11:59 AM, vamythguy <vamythguy at gmail.com> wrote:

>
> So I guess part of my issue with the RAID stuff is how I've got 3x250 and
> 1x300 in a RAID5 array, so I'm missing 50G.  This is because I had a 250 go
> bad and replaced it with a 300.  Ideally, that extra 50 would've just been
> brought in and be usable - even if not RAID5.  Maybe I'm looking for too
> much.  I've had problems before with making a decision one way and then not
> being able to change it (because of the size of the filesystem), so I'm
> trying to be smarter about it.
>
> All of which skips my other issue, that being the reclamation of that
> orphaned array and figuring-out how to get back at it (given I've had issues
> in the past with moving the disks of an array to a new mobo, a new instance
> of mdadm, whatever, and having it not be recognized).
>
> Finally, is a multi-port eSATA solution a good way to externally house
> these drives?  Is AoE a real option?
>
> I know, I'm all over the place here...
>
>
I'm sure my response will be all over the place too.

My setup for reference:
-- Older Array(s):  6x300.
   Partitioned into multiple arrays, boot (raid1-ext2 - 6 way :-) ), root
(raid5-ext3), diskless(raid5-ext3),  music (raid5-xfs), "stuff"(radi5-xfs)
-- New Array:  4x750 video(raid5-xfs)  - in 5 bay hot sway chassis, running
5->1 Port multiplier on 1x PCIe card.

Some comments in no particular order:

- I don't like LVM on RAID.  Extra layer of SW. In my testing..it was much
slower. Doesn't really provide much benefit. Although if you already have
it, then I guess you'll want to stick with it. I ditched it when i grew my
1st array from 3x300 LVM to 3x600 multiple partitions.

-- You can resize RAID5 now.   In my experience it works very well.  There
are two essential scenarios:

Repartitioning Arrays within disks: This is interesting procedure.. but
worked well.  You had to force fail each drive from the online array, then
re-partition [delete all the partitions] on the raw drive, then add the
drive back to each array, wait for re-sync then rinse-repeat for all
drives.  This way you can completely move partitions, and resize them bigger
(not smaller obviously). Once all "partitions" within an array are re-sized,
you can then re-size the filesystem.  One fs i used forced me to reboot. :(

Adding Disk:  This is the new one.. It's very slick. I grew my 2nd array
from 3 drives to 4, completely hot & online, while recording many GB of
Olympics.

-- As far as RAID5 for mythtv & HDDs being reliable.. I disagree.  I had 4
non-raided hdds die in the span of 12 months.. that's when i went to a main
fileserver for all storage. Since then I've had 2 of those 10 (+1) drives
die, quickly replaced, no data loss.  Yes, it's it not the end of the world
when you loose recordings... but you can explain that to my wife.

-- I would recommend a separate media for the OS.  Mine's on the 1st array,
and it's annoying there if i want to change something.  Recently I built a
system for someone with root on a IDE-> CF. That worked well.

-- The 5->1 port multiplier stuff is pretty cool. Coupled with the hot swap
chassis. I was able to cram another whole array into a server with already 6
drives.

-- The allocation of /dev/sd?? should not be an issue for an array. The
order at which my drives come up is quite variable, and they get different
letters all the time.

I would be glad to elaborate on anything if people want.  My next big debate
is what to eventually replace the 300s with.
--Dragon
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