What to do with 7 drives?

[murpmich59]

OK, I have spent several hours searching and browsing threw posts. Need help to point me in a general direction.
In the mail on the way: Asrock EP2C602-4L/D16 dual LGA 2011 motherboard
2 ea Xeon E5 2670 v2 10 core CPU's
128gb (16eax8gb) DDR3 1600mhz registered ECC ram

Going to use server for documents, files, and pictures which I don't want to lose. Also want space for plex media content which wont matter that much if it was lost (can always reload to server).
Question is how should i set this pool up with seven drives? Should I get 1 more drive and run 6 on zfs3 then 2 drives striped for plex media.
Any suggestions would be appreciated.

Thanx

 

[Jailer]

I'd just run it as one pool. How you configure it is entirely up to you depending on how much space you need.

 

[murpmich59]

noted, Thank You

 

[Evi Vanoost]

3 2-way mirrors and a spare? This will give you the best performance, fastest recovery and easily expandable. Otherwise 6 RAIDZ2 and a spare, you gain a 'slight' bit of space but at the expense of both performance and recovery speeds. Expansions almost require another 6 drives.

I wouldn't split the system into multiple pools, just split the pool in multiple volumes unless there is an absolute reason you need the bottom of the can performance (unless you're going 10Gbps+ it most likely won't make a difference). This way you won't waste space or performance.

 

[Arwen]

Part of the issue in splitting up the disks into multiple pools is that you can't share space between them.
If you run out of space in one pool, you can't realocate the space to the other pool without a total data
rebuild. That means full backup, (or 2), destroy both pools, re-create then restore. Not a simple operation.

So, for 7 disks, a single RAID-Z2 might work out the best. Put things in different datasets, perhaps with
different dataset properties, (for example, absolutely critical files in a dataset with "copies=2").

This is one of ZFS's weak areas. I wish I had the ability to specify RAID-Z1 for my media, RAID-Z2 for
normal stuff, backups and such, and RAID-Z3 for my personal items, (photos and my own written software).
All of this on the same set of disks. In essence, a super hybrid pool.

 

[Evi Vanoost]

You can do something like it. Set copies to 2 on your dataset and the pool will contain 2 sets of data across failure domains. Obviously RAIDZ3 on 6 drives has the same capacity as mirrors and way worse performance. I highly recommend mirrors over RAIDZ levels until you get to ~10-14 VDEVs.

 

[Jailer]

Obviously RAIDZ3 on 6 drives has the same capacity as mirrors and way worse performance

It depends on use case. There are plenty of use cases where the performance of RAIDZn is more than adequate.

 

[murpmich59]

I had to go back and look at Cyberjock's notes, he mentions, "The new VDev does not have to have the same characteristics (mirror,Z1,Z2,etc) howerver it is highly recommended." Cause at first I was thinking of running Z2 or 3 on part of the pool and mirror on another VDev. I'm getting the impression this isn't a good idea?

 

[Robert Trevellyan]

I was thinking of running Z2 or 3 on part of the pool and mirror on another VDev. I'm getting the impression this isn't a good idea?

Mixing vdev types within a pool is not recommended, because you kinda get the worst traits of each, i.e. the pool is only as reliable as the least reliable vdev, while the performance benefit is essentially based only on the number of vdevs. But maybe you were actually thinking of multiple pools, each with a different vdev layout. That's fine, though potentially less convenient than a single pool.

 

[murpmich59]

Well I think I might have came to a self-conclusion after reading all morning through the forums. All my thousands of pictures I want to be relatively safe, and plex movies not very important, I will go ZFS2 (4+2) for my first Freenas server. Question is should I set my extra drive on the shelf (cold) or install it as a hot drive? Usually I'm close to home but sometimes I'm out of town for 10 days or so.

Thnx for all your help guys

 

[Jailer]

Burn it in and test when new to rule out infant mortality while still under warranty. If it passes put it on the shelf as a known good replacement for when a drive fails.

 

[Evi Vanoost]

I'd recommend a hot drive. Even if you're present, inserting a drive takes time if you even notice on time and there is the potential of something going wrong when you do things manual (adding it as a VDEV instead of a spare)