proxmox on small computer using zfs for storage only

[sz3bbyla]

I have an small computer with proxmox
Intel(R) Celeron(R) J4125 CPU, 16G ram
installed on one nvme 512GB samsung evo ext4
with 3 lxc

I want to add 2 hdd toshiba 8TB each and to use it as zfs mirror for data stored on this home based computer
I don't know about zfs to much but what I understand is very stable

there is any way to use as zfs ? how much memory must alocate from ram to it , using compression or any advice is welcome
or is beter another type of partition like raid or btrfs for this small configuration to don't stress to much that hdd's

 

[UdoB]

Recommendations will vary drastically, including to avoid ZFS on such a small system. My version:

I want to add 2 hdd toshiba 8TB each and to use it as zfs mirror for data stored on this home based computer

Go for it! You will get reliable data, including "self-healing" if a block or a complete disk fails. Even though using "HDD only" is slow. From my point of view it is not usable for storage used as a VM datastore and especially not for a PBS one. It is fine for "normal" data though - your documents will be happy to live there.

To enhance this low-performance-problem you could add a mirror of SSD/NVMe as a "Special Device". Often this is difficult because there is just no unused SATA/NVMe-connector available for this on a Mini-PC...

You have only 16 GiB Ram. For "normal data" a single GB for ARC may be sufficient. The classic/old rule has been 1 GB Ram per TB data --> 8 GB Ram in your case, which is not a good idea for your system. Look here and start with 2 GiB for ARC: https://pve.proxmox.com/wiki/ZFS_on_Linux#sysadmin_zfs_limit_memory_usage

Leave the settings (compression, blocksize etc. pp.) as they are by default; only change them if you have a specific reason.

Good luck

 

[sz3bbyla]

thank you very much
So this smal computer is a AS6602T lokerstor 2

I can reinstal proxmox on zfs raid mirror 2 nvme samsung (I already have and this computer have 2 sata/nvme and 2 hdd drive 3.5) , can increase max 32 gb ram and the 2 x 8tb for data storage to be used as well as zfs mirror ? is a good ideea ?
to be honest I used a litle bit with 3 lxc like pihole, torrent, and lamp(only local) , in special is used for storage and I will make one more lxc onecloud and my problem is I got io delay if I USE TORRENT + FILECOPY, 50% to 90 % delay
files copy in nas to be more explicit

this is why I ask how much ram to alocate for zfs and which tuning can help me on this small config

 

[UdoB]

this is why I ask how much ram to alocate for zfs and which tuning can help me on this small config

Maximize your RAM! Give ZFS as much RAM as you can; try not to outsmart ZFS by adding an SLOG or a Cache without much more reading and understanding how those work and what they can not do.

If you are ok with a reinstallation: during the fresh setup install PVE onto the HDDs, as a single ZFS mirror. After everything is up and running add the mentioned "Special Device" - consisting of two (or more) fast devices in a single mirror. (As far as I remember this can not be done from inside the installer, so it has to be done after installation.)

Search for "special device special_small_blocks" to find some info regarding better usage of that Special Device. Without an optimization it will use less than 1% of the size of the HDDs. (For 8 TB HDD it will only use less than 80 GB. If you do not prepare for better use the remainder of a larger disk will never be used --> wasted.)

That "Special Device" will store all metadata. And depending on that "special_small_blocks" setting also some data. This approach at least doubles the IOPS of the bare HDDs because less physical head movements are necessary and accessing meta data is as fast as those NVMe are.


For completeness sake, not mentioned yet: always have a backup. And another one. And a third one off-site.

 

[sz3bbyla]

thank you UdoB , but , to be honest I'm not very clever in this domain. Reading fast some info don't make me to understand exacly how function this special device
For me to install all proxmox in 2 ssd 500GB zfs mirror is more than enough space with lxc's and images and backup
the other 2 hdd's I want to have it only for my data (movies pictures etc)
computer is not very powerfull but when I need to connect to it was enough good
I need optimistions if is possible just to reduce that IO delay
if I used only as samba to view my docs was ok
if i used only for downloading some torrents was ok too
in combination I figure out begins that big IO delays
I do not try to create to many things with this proxmox, but is give me posibility to stop one lxc if I want or easy replace the lxc
if I use asusstore software don't make me feel very confortable

all I try to understand is an easy way to make it usable in his limit

I will change ram to it before to make it stable
I set max ram and minim ram in modprobe.d
first 3gb max and 1gb min
after 6gb for max and after 8 for max ram
to be honest for me the best was with 3 but ...

 

[UdoB]

Everything is fine as long as it is okay for you. Of course larger/faster/better/greater systems are more complex too and need more understanding of the details.

I just gave you a clue what _I_ would do in your case with limited hardware, but my expectations and my willingness to dig into those details are obviously different from yours.

The lowest effort to enhance performance is to maximize RAM; everything else is more complicated. At least as long as you do not want to switch 8 TB HDD into 8 TB SSD - which is technically easy ;-)