Hello,

 

I installed a couple of 2TB Samsung NVMe SSD's in my server a month or so ago.  I had a single smaller 250GB drive in there before that had my appdata folder on it for snappy Docker access...and since replacing it with the 2 larger drives, I am still using only for that as I've been doing some testing to see what I think would best suit my needs for how to use to drives.

 

I think I've settled on the idea of using the drives for all my torrent downloads, but also use the cache-first options for my shares where the downloaded content finally ends up on the array. That way, I can download something, then with hardlinking enabled, copy it to the destination share, which will still be on the cache drive, so it should be an instant copy...then the mover and move it to the array in the night.  With hardlinking on too I won't use double the amount of drive space on the cache pool when doing copies.

 

Anyway...what I want to know before i steam ahead is, which file system should I go for?  I set the 2 drives up as a ZFS pool when I installed them just for sh!ts and giggles, but I know very little about ZFS and am not sure whether it's the best FS for my uses?  Should I be ZFSing or go with BTRFS?

 

I noticed when I set up the drives, I got a new memory usage bar on the dashboard for ZFS. It is set to 2GB.  Is it automatically set to 2TB cause I set the drives up as a ZFS mirror and it's 1GB per 1TB (which I believe is the recommending memory allocation for ZFS?)

 

I appreciate any advice!

I have been researching a bit about ZFS lately because I have setup a all NVME MiniPC Unraid server recently. From my research it seems well documented that when you use drives that are not spinning drives with ZFS, it tends to leave allot of performance on the table. The general consensus I have found is that you don't want to run ZFS unless you want to use some of the file systems advanced features like De-Duplication, Snapshots, ect. When those features become a factor it is very difficult to replace ZFS as the best option. 

 

I have yet to find a anyone that claims they can get anywhere near max performance form NVME drives with ZFS

 

As far as your memory question, you may want to read the initial release info for the feature. I believe it stated that it is going to be configurable eventually, but for now it is set to 1/8th the total memory of the system. ZFS can be very memory intensive in a large scale deployment. There are also allot of features that will be coming with ZFS in the next release based on that blog post. 

 

It would be interesting if we could get some benchmark numbers between ZFS and BTRFS. 

In my experience for a two pool mirror btrfs and zfs preform very similarly for writes, reads are usually faster with zfs since it stripes reads from both devices.

Thank you for the advice.

 

I wiped the drives not long after my original post at the start of January -- getting rid of the ZFS pool and setting it up as BTRFS.  Has worked like a charm so far.  Hard linking works without issue across shares.  I have not stressed tested how much throughput I get with my setup (not sure the best way to do this on Unraid?)...but I should preface, although I am using Samsung 970 EVO Plus drives, which are PCIe 3.0 x4, cause my board is an X470 motherboard with only 2 NVMe slots -- I think because I have 2 of the PCIe slots occupied (GPU & HBA controller), one of the drives is running at PCe 2.0 x4...if I have understood the mobo manual correctly.

 

I would be interested in running a test though to see what the max read/writes of the BTRFS pool would be, if anyone knows?

Does anyone also know if there is a way to see what PCIe gen and number of lanes each of the drives are using, so I can confirm?

Thanks!

7 hours ago, Stupot said:

Does anyone also know if there is a way to see what PCIe gen and number of lanes each of the drives are using, so I can confirm?

lspci -vv will show that, you can limit the output to the device you want, see the --help

Hi, I am going to change unraid to a new computer and I have taken the opportunity to take 2 m2 Pcie 4.0 SSDs of 1TB each that I will use as a mirror cache. Today, which option would you choose for this, ZFS or Btfrs?

Edited November 9, 20241 yr by bmwjavier

ZFS, it's better a recovering from a dropped device.

52 minutes ago, JorgeB said:

ZFS, it's better a recovering from a dropped device.

Ok thank you! And xfs for de array, right?

That's the recommended one for the typical user.