<div>Been running a software raid 5 for a few years (PATA even) with little issues. Using hdparm for speed tests helped me to tweak the stripe size and such. IIRC, it was about 3-4 times faster reading from the raid than from a single disk.
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<div>I don't write myth recordings to it, I use unRaid for my myth recordings. Check it out, it's free for just three drives, but you'll require another computer.<br><br> </div>
<div><span class="gmail_quote">On 10/25/07, <b class="gmail_sendername">Patrick Wagstrom</b> <<a href="mailto:patrick@wagstrom.net">patrick@wagstrom.net</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Greg Arena wrote:<br>> I just recently bought a trio of 500 GB SATA hard disks<br>> that I want to put together in a RAID 5 configuration for my
<br>> MythTV box. These will only be used for storing recordings &<br>> videos - I have an 80GB PATA drive in place that I'll keep there<br>> for the OS, MythTV software, logs, etc. I plan to use Linux's
<br>> software RAID support - true hardware RAID was just too<br>> expensive.<br>> I've heard mixed reports about using RAID 5 for media<br>> stuff. The MythTV wiki doesn't recommend it without expensive
<br>> hardware RAID controllers, but yet I've heard people talking<br>> about their RAID 5 setups on this list and elsewhere. I was<br>> wondering if anybody has gotten something similar working and<br>> what settings they used (stripe size, etc.) since I've never set
<br>> up a RAID before. I've already run some benchmarks using bonnie++<br>> with one drive by itself to use for comparison after setting up<br>> the RAID to try to make sure it's not going to degrade<br>
> performance excessively. I'm willing to spring for another hard<br>> disk to go to a four-disk RAID 10 configuration if RAID 5 looks<br>> like it'll be too slow.<br><br>I'm not an expert on raid or filesystems by any extent, but I've had no
<br>problems over the past two years running a 4x320GB SATA2 RAID5 array<br>with XFS on it. The actual amount of disk IO that MythTV needs to do is<br>pretty small, a couple of megabytes a second at most. I've tested this
<br>with 3 HD and an SD recording with HD playback going on at the same time<br>on an Athlon 64x2 4400+ with no problems.<br><br>Performance wise, here's a comparision of block performance from Bonnie++:<br><br>IDE drive: Output 49971K/s, Input 50581K/s
<br>SATA raid: Output 43444K/s, Input 154578K/s<br><br>So yeah, it's a little slower for writes, but it's nice and fast for<br>reads. In any case, 43MB/s is fast enough for lots of HD streams. When<br>you have parallel readers/writers, the issue gets a little worse, but
<br>you still have enough overhead there for seek issues...which you'd have<br>on RAID10 anyway.<br><br>> I'm also considering using XFS for the file system for<br>> storing all the media files on this RAID. Any suggestions on how
<br>> to optimize it for RAID 5 or RAID 10? I've never used anything<br>> but ext3 for my Linux boxes until now, so I'm new to XFS as well.<br><br>XFS is a good choice. For Myth folks, one of the big advantages is that
<br>it's extents based, so deletes are pretty fast.<br><br>--Patrick<br>_______________________________________________<br>mythtv-users mailing list<br><a href="mailto:mythtv-users@mythtv.org">mythtv-users@mythtv.org</a>
<br><a href="http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users">http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users</a><br></blockquote></div><br>