[mythtv-users] RAID suggestions?

[Ma Begaj]

I have raid5 with three 500gb sata disks in one fileserver and I am
using software raid5 (reiserfs). I did not want hardware raid anymore,
because I had it for 4 years and the raid card died. it was very hard
to recover data, because I was not able to find a similar card for a
long time. I decided after that to use software raid5 and I never had
any problems for 3 years. It was just bad luck with a raid card, but
that was enough.

I tested it two years ago, and I can remember that it was around
20-25% slower than writing to one disk. Reading was pretty ok, but I
do not remember how fast was it. you will see that your cpu is working
more than usual, but I don't care about it, because this box does
nothing else. I have LVM over this raid and other two raids and lvm is
probably making it even slower, but it should not affect it so much. I
like this configuration because it is easy to expand and manage with
raid5 and lvm.

I was using this raid5 for a few months as a recording partition for
mythbackend and I had no problems with one reading and two recordings
at the same time. but as I said, cpu (athlon x2 3800+) was pretty
busy. I am not using it any more for mythtv recordings, because I have
now enough space in the mythbox..

M.


2007/10/25, Greg Arena <gma at gmadigitaldesign.com>:
>         I just recently bought a trio of 500 GB SATA hard disks
> that I want to put together in a RAID 5 configuration for my
> MythTV box. These will only be used for storing recordings &
> videos - I have an 80GB PATA drive in place that I'll keep there
> for the OS, MythTV software, logs, etc. I plan to use Linux's
> software RAID support - true hardware RAID was just too
> expensive.
>         I've heard mixed reports about using RAID 5 for media
> stuff. The MythTV wiki doesn't recommend it without expensive
> hardware RAID controllers, but yet I've heard people talking
> about their RAID 5 setups on this list and elsewhere. I was
> wondering if anybody has gotten something similar working and
> what settings they used (stripe size, etc.) since I've never set
> up a RAID before. I've already run some benchmarks using bonnie++
> with one drive by itself to use for comparison after setting up
> the RAID to try to make sure it's not going to degrade
> performance excessively. I'm willing to spring for another hard
> disk to go to a four-disk RAID 10 configuration if RAID 5 looks
> like it'll be too slow.
>         I'm also considering using XFS for the file system for
> storing all the media files on this RAID. Any suggestions on how
> to optimize it for RAID 5 or RAID 10? I've never used anything
> but ext3 for my Linux boxes until now, so I'm new to XFS as well.
>         Of course, since I'm new to RAID and XFS, I'm not going
> to put the RAID online until I'm sure it'll perform well and
> reliably - I definitely plan to experiment before I shift the
> handful of recordings & videos I've squeezed onto my current Myth
> partition over to the new RAID.
>
> Thanks,
> Greg A.
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>


-- 
Glauben heißt nicht wissen wollen, was wahr ist ... Nietzsche