Segregating zpools based on usage type

[scurrier]

Is segregating RAID arrays (Or RAIDZ arrays) based on usage type a good practice?

For example, I am currently planning my NAS and am at the stage of buying drives. My uses for the NAS will include:

1. Keeping valuable family memories
2. Holding files such as tax documents
3. Holding movie backups
4. Holding recorded TV shows from my HTPC
5. Serving as storage for revolving security cam recordings

As you might imagine, items 4 and 5 will involve a high amount of constant writing. Which I am equating to 4 and 5 being the highest contributors to disk wear. So, if items 4 and 5 will be the highest in terms of wear, it might be wise to give them their own array so that they do not wear out a large pool of disks. Instead, give them a smaller array and let them wear out a small pool of disks (possibly more often).

Good idea or not?

 

[cyberjock]

It's a "good" idea if you can handle that kind of granularity and you are concerned about minimizing fragmentation since you can never really defrag ZFS.

It's a bad idea if you were wanting to do that with less than 5 hard drives since you'd need 1 disk per pool(that's minimum with no redundancy).

But, you know what I do? I just do 1 big pool and not concern myself with stuff like that. There's so many other ways to get things wrong simpler is better, especially for your first run around the track with using a FreeNAS box in production.

 

[scurrier]

Well I have 10 hard drives already so using some of those old ones for a "wear me out" pool is not an extra cost to me. I hadn't thought of fragmentation in this context. There's another reason to do it.

I usually agree that simpler is better but in this case I think there is enough of a benefit to warrant it.

 

[cyberjock]

There's other factors to consider when doing what you are doing too.. mirrors versus raidz2 will cause difference performance characteristics and different expected reliability patterns. Strictly from a performance and reliability standpoint doing a single RAIDZ2 is going to be better than mirrors. So while you say you think there's enough of a benefit, I'd beg to differ. But, it's your server so your rules! That's what's so great about FreeNAS.