To unraid or not unraid

[Ancan]

Hi,

I'm looking into alternatives for my future home server/storage setup, and hope to replace both my current ESXi server and Synology NAS with one box. I currently have a Dell Perc hardware RAID with 6 x SSD in RAID5 for my vmware datastore needs (speedy), and the Synology is for bulk data and holds CIFS shares plus nfs export to the ESXi for large datastore (roomy). My VM's are a handfull of Linux servers, and two Windows servers.

 

My new hardware will be like this:

* Silverstone DS380 chassie, with 8 x hotplug 3.5" plus 4 x internal 2.5" slots.

* Ryzen 2600

* ASRock B450 motherboard with 4 x SATA

* LSI MegaRaid 9211-8i in IT-mode.

* 32GB RAM

* Small 50GB SSD M.2 on the motherboard (thought to be the boot device, but guess it would be cache if I go with Unraid).

 

My plan have been to have the 8 x hotplug slots be connected to the LSI controller, and fill them with HDD's, and then have the 4 SATA connectors on the M/B serving 4 x SSD's, and still have both a small/fast array for VM's system disks and a slow/big one for data.

 

I haven't got the parts yet, but have set up Unraid virtualized in my current ESXi host. I soon realized you can't have multiple arrays, so having dedicated SSD storage for the VM's seems more or less out of the question (correct me if I'm wrong) - I can limit them to only be on the SSD disks, but the parity will still be on one of the large HDDs.

 

Is it possible to do an alternative configuration for this in Unraid, or am I looking at the wrong product? Should I go with one of the alternatives that use a more traditional RAID-set approach?

 

Thanks for your input!

 

 

 

 

 

[itimpi]

The way to handle the SSD's in Unraid would be to use them as a BTRFS cache pool.  The default with Unraid is to set up a cache pool as BTRFS style RAID1 (although you can manually set up other RAID configurations) and that gives a level of built in redundancy although it is still good practice to back up the VM vdisks elsewhere (typically to the array).

[trurl]

Since you didn't mention the cache pool it sounds like you were thinking of using the SSDs in the parity array. Lots of reasons to NOT use SSDs in the parity array. The most obvious is the write performance hit due to realtime parity update. Also, SSDs in the array cannot be trimmed. And it is suspected that some SSD implementations might invalidate parity.

 

The way to get a separate "small fast array" is with the cache pool. See the Overview in the Wiki for more:

 

https://wiki.unraid.net/UnRAID_6/Overview

 

That M.2 is probably too small to be useful. You might find some special use for it as an Unassigned Device.

[Ancan]

Thanks!

I published three more SSD disks to my "lab" Unraid VM, have assigned them as cache devices, and created a "vm-datastore" share that is set to *only* use the cache disks. This was how you meant, right?

 

 

 

Is the cache on btrfs RAID1 now? A bit unclear, but I assume since it's part of the cache pool it is.

 

How would I do to change this to RAID5 instead? I tried adding more disks, but there was some manual configuration also.

 

What if I want the cache to also be used to speed up the remaining shares. Will it risk becoming full from changes? Can I set aside part of the cache for one share?

 

 

 

[trurl]

Are you intending to run Unraid as a VM? Unraid itself can host VMs in case you didn't know.

 

If you intend to run Unraid as a virtual machine in VMWare or some other OS then I will move this discussion to the appropriate subforum.

[unabletoconnect]

Further to this my understanding is that BTRFS in RAID5 is still unstable and its only a matter of time until you have data loss if you use it.

[Ancan]

9 hours ago, trurl said:

Are you intending to run Unraid as a VM? Unraid itself can host VMs in case you didn't know.

 

If you intend to run Unraid as a virtual machine in VMWare or some other OS then I will move this discussion to the appropriate subforum.

No, this is just my lab I created to get a feeling of the product. I'm still waiting for the new hardware.

 

I know that there's an hypervisor as well, and it's my intention to use that if I go with Unraid. Been trying it out a bit with a small Ubuntu server installation, but the VM always abruptly shuts down in the middle of the installation, so I first impressions haven't been great.

 

 

 

 

 

[JonathanM]

If you are trying to use unraid's KVM instance when running unraid itself as a VM, that gets really hairy. I wouldn't even attempt nested VM's unless I had a really good reason to spend a bunch of time troubleshooting.

https://www.virtuallyghetto.com/2014/09/how-to-run-qemu-kvm-on-esxi.html

That article is rather dated, but I don't think VMWare has progressed that much since it was written.

[Ancan]

1 hour ago, jonathanm said:

If you are trying to use unraid's KVM instance when running unraid itself as a VM, that gets really hairy. I wouldn't even attempt nested VM's unless I had a really good reason to spend a bunch of time troubleshooting.

https://www.virtuallyghetto.com/2014/09/how-to-run-qemu-kvm-on-esxi.html

That article is rather dated, but I don't think VMWare has progressed that much since it was written.

Oh, I got it to work just by allocated more RAM to the Unraid VM. Guess it was the OOM killer that hit it. Still having issues with speed and networking, but don't know if it's because they are nested. VirtualBox nested is much faster than what I'm seeing in Unraid.

 

My current experience from tinkering with different NAS softwares the last few days, is that I'm not 100% satisfied with any of them, and it's often the virtualization component that disappoints for one reason or another. Perhaps I'll give all another try when the gear has arrived, and I can run everything on the hardware.

 

I really like many features of Unraid, such as mixed drive sizes (and the polished interface), but as of now my "plan A" has become to run ESXi on the server, and then one or other NAS product virtualized on it.

 

 

[trurl]

1 minute ago, Ancan said:

Still having issues with speed

Speed of what?

[Ancan]

18 hours ago, trurl said:

Speed of what?

VM's in general are much slower than on VirtualBox which I also run nested.

 

I've moved my Unraid test installation to a physical machine now, so I can see if it works better. Only one HDD and one SSD in that one, so I cCan't try out all the disk configurations but I'll see if the virtualization part is working better.

[Ancan]

To end this "pre-sales" post, for me it seems Unraid works much better "on metal" than what I set up virtualized in VMware. I've got both a debian headless and a Win10 VM running without problems, which is about what I can cram into my test-PC. They also run about the same speed as they did stacked on on my vmware host, but that Xeon has a CPU 3x the speed compared to the i5-650 they are on now so it's an improvement.

 

I realize I can't have the dedicated SSD array for VM system disks quite in the same way as I did before, but I hope having this stuff on the cache will be well beyond "good enough" anyway.

 

Unraid has sailed up to top choice for the new home server, but I'll keep tinkering with it for a while more while I've got the trial license just to be sure, and will probably pester you with more questions meanwhile.

 

Thanks!