<div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Is anyone recording directly to RAID? If so, what type/size, how many<br>
simultaneous recordings and how well does it work?<br>
<br>
I'm currently using 3 independent drives for recordings. The primary<br>
reason to use independent drives has been to spread in-progress<br>
recordings across multiple spindles. It's fairly common for me to<br>
have 3 or 4 simultaneous recordings and 6 is not unheard of during<br>
some busy parts ot the year.<br>
<br>
While my drives currently aren't on death's door, they are a few years<br>
old now and I have had a handful of scares in the last few monoths<br>
where various drives (or controllers) have gone wonky. Fonrtunately,<br>
the wonkyness has only been temporary and I haven't lost anything of<br>
real importance. Still I'm spooked enough to seriously consider<br>
adding some redundancy.<br>
<br>
The two configurations I'm primarily considering are either a 4-disk<br>
RAID6 array or a pair of 2-disk RAID1 mirrors. While the RAID6<br>
configuration should be more reliable, in theory, I'm leaning toward<br>
the RAID1 configuration. One big reason, and the reason for this<br>
email, is the increased seek load on all drives with RAID6 when 4 or<br>
more recordings are in-progress.<br></blockquote><div><br></div><div>First of all... with 4 drives, a RAID 10 or 01 would be best. But do yourself a favor and DONT USE RAID.</div><div><br></div><div>I ran a variety of RAID configurations over the years and have finally seen the error of my ways.</div>
<div><br></div><div>Mythtv works best with multiple drives in it's storage groups and does a wonderful job spreading the load out. With my arrays, I would hear the drives thrashing as I recorded 2-3 channels, watched one recording, and had a commflag running, the heads were all over the disks; because the array used all of the disks for each of 5 processes. Now, with 4 independent disks, typically each disk is handling one or 2 of those processes... which rarely taxes the drive.</div>
<div><br></div><div>Additionally, software raid has significant overhead... so a few percent of my processor was dedicated to just handling the IO.</div><div><br></div><div>Finally, RAID does nothing for you if your data is corrupted. For example I ran a transcode job on an entire season of a show and realized afterward that the transcoded shows were unwatchable. RAID can't help you get them back... really killed the WAF.</div>
<div><br></div><div>So I broke my arrays and now only back up the stuff I actually need (use storage groups to keep important and unimportant recordings organized) to an external drive using rsnapshot (highly recommended). Additionally, I copy my database and some other important data off to an internet based service.</div>
<div><br></div><div>If you have 4 drives and are willing to lose 50% for redundancy... a real backup is a far better use of that extra space than RAID will ever be.</div><div><br></div><div>I bought a 2TB external esata drive just for this purpose so I could use my existing drives for recordings.... so I doubled my storage with that purchase and improved the performance and reliability of my system at the same time.</div>
<div><br></div><div>Recovery is easy... if I lose a drive, I can simply copy the recordings from the backup into any of the existing storage groups, assuming there is room... or add the backup folder to the storage group until a new drive arrives.</div>
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