Freenas Mini XL questions

[cryptyk]

Hi,
Two quick questions about the Mini XL:
1) Is it powerful enough to transcode a single 4k stream with plex?
2) I'm thinking about buying the XL, but only putting 4 drives in it at first. I'll add more later as I need more storage. Is there any reason that's a bad idea? I want to make sure it doesn't work "better" only when all of the bays are filled out or something.

Thanks!

 

[Stux]

Not sure about its CPU power, but regarding expanding it, you just need to be aware of the limitations on adding additional disks to a pre-existing pool.

If you use mirrored drives, there's no problem. If you use raidz1 or raidz2, then in order to grow to an 8 way RAIDZ2 Or Raidz1 (not recommended), you will need to backup, reformat the disks, and restore.

Performance should increase with additional drives.

 

[mrichardson03]

Hi,
Two quick questions about the Mini XL:
1) Is it powerful enough to transcode a single 4k stream with plex?
2) I'm thinking about buying the XL, but only putting 4 drives in it at first. I'll add more later as I need more storage. Is there any reason that's a bad idea? I want to make sure it doesn't work "better" only when all of the bays are filled out or something.

Thanks!

1. I don't think so. I was experimenting with Plex transcoding a straight Blu-ray rip on mine (I don't have any 4k content), and CPU utilization was around 50%. If you've got gobs of disk storage, you could always store a second already transcoded copy, either by using Optimized Versions in Plex or running it through something like Handbrake. I've been thinking of doing this myself.

2. Just fooling in the GUI, I looked to see what FreeNAS recommended to me with 8 drives. I had been thinking about either running a single RAIDZ2 or RAIDZ3, but I was recommended a 2x 4 disk RAIDZ2 configuration. The more I think about it, the more I like that idea. With a 4 disk initial setup in this configuration, you could set up one RAIDZ2 and then extend over it when you need more drives. You can add an identical vdev to the one you have and stripe over it (second 4 disk RAIDZ2), but you can't change any vdev you already have without deleting the pool and starting over (4 disk RAIDZ2 to 8 disk RAIDZ2).

 

[cryptyk]

These replies are super helpful. Thank you. I really appreciate it.

On the point about extending from 4 drives to 8, I want to make sure I understand; I'm not a raid expert :)
If you'll allow me to play that back so you can correct it:
I can't just add four more disks to an existing Raidz array. I need to reformat to do that. This makes sense to me because each write it striped/paritied individually and deconstructing each of those and redistributing it across a new set of disks sounds "really hard".
I can take a 4 disk Raidz array and set that up as a vdev ("vdevOriginal"). It would be the only vdev in the pool when I start.
Later, I can add 4 more disks as a second Raidz array and configure them as a new vdev ("vdevExtend").
Now I have two vdevs and I can configure them as a single pool.

I'm assuming that the pool is the mount point, right? As far as BSD is concerned, the drive will just be bigger all of the sudden.
I'm also assuming that I can configure that pool to either mirror data across the vdevs (which will increase performance and reliability), or to stripe the data (which will increase performance and volume size). My brain hurts when I think about striping writes across two parity volumes, but I trust that someone smarter than me is in charge of how that works :)

On the earlier point about Plex performance:
I'm more than capable of building my own high performance system. I've been building them since I was a kid. I just really don't want to spend the time right now selecting components, buying them individually, then putting everything together. That's why I was leaning towards the Mini-XL. Is there an option somewhere between an "underpowered" Mini-XL and spending weeks getting up to date on all of the latest components, figuring out what works together, then hoping FreeNas/BSD have reliable support for those components? I'd love to buy a pre-built system that "just works" and is more powerful. Barring that, I'd love to find a parts list from someone who already figured out the right mix of components.

Thanks again for your thoughts!

 

[danb35]

Now I have two vdevs and I can configure them as a single pool.

Correct so far.

I'm assuming that the pool is the mount point, right?

Yes. The pool is what FreeNAS calls the "volume."

I'm also assuming that I can configure that pool to either mirror data across the vdevs (which will increase performance and reliability), or to stripe the data (which will increase performance and volume size).

No. When a pool has multiple vdevs, data is always dynamically striped across all vdevs. This is why pools are rather like the Hotel California--vdevs can check in at any time, but they can never leave (at least, not without destroying the pool).

Take a look at @cyberjock's presentation on ZFS basics if you haven't seen it yet; it should help you out on this subject.

 

[cryptyk]

I just read the powerpoint. That helps a LOT.

One last question on the array:
I'm convinced that a single vdev with 4 disks is how I will start (in an 8 bay case). Later, I'll add another vdev with 4 disks to fill out the case.
My question is whether I should configure those 4x disk vdevs as Raidz2, or as a 2x2 mirror. If I understand correctly, the usable disk space will be the same (2 disks), but the mirror will be easier to recover a disk, if needed.
Is that right?

 

[Stux]

The 2x2 mirror will be more performant for random iops.

You can expand to 3x2 and then 4x2, and then upgrade any of the x2s to larger disks with the mirrors.

But if the right two drives fail, you can lose a mirror and thus the pool.

With raidz2 any two drives can fail without losing the pool.

If capacity is more important to you, I'd use 8 drives in a single raidz2.

If iops is more important, and ease of expansion, use mirrors.

 

[cryptyk]

Got it. That makes sense. In any mirror scenario, you can lose the "wrong" two drives and the vdev is gone. With Raidz2, you can lose *any* two drives and still be ok.

Anyone have any thoughts on the hardware? Is there a pre-built system that is more powerful than the Mini-XL? Alternatively, is there an easy way to upgrade the CPU in the Mini-XL?

Thanks! You guys seriously rock.

 

[Stux]

I think the short answer is not in that size.

 

[cryptyk]

I don't really care about the size. I prefer that it's not rack-mount, though. As I look through the forum, I see a few folks using SuperMicro servers with success. I'll keep reading :)

 

[danb35]

Is there a pre-built system that is more powerful than the Mini-XL?

Sure, tons of them, but I doubt you'll find them in that form factor. The Lenovo TS140 or TS440 are both available with Xeon CPUs which would be quite a bit more powerful. @Mirfster likes his Dell C2100s, which hold up to 12 drives and are pretty cheap (here's one), but are an older generation and will draw more power. Really, most fairly-recent Dell/HP/Lenovo/SuperMicro servers should work just fine, but you'd ideally want one without a hardware RAID controller. But none are likely to be as compact or quiet as the FNMiniXL.

Alternatively, is there an easy way to upgrade the CPU in the Mini-XL?

No. The CPU's integrated into the motherboard and can't be changed.