info setup raid software

[ale.ab]

Hello,
i have a proxmox server from few years with this configuration
1 cpu 4core/8threats 32gb ram 2x2tb raid1 software with proxmox 6 (isp provided with ext4 without LVM)
now i bought a new server with this hardware
1 cpu 8core/16threats 32gb ram 4x2tb raid software
but now i have ipmi so i try to attach iso of proxmox 7 and setup with zfs raid 10.

proxmox would run 6/7 VM with total 26GB and 800/900gb storage

so my question is.

can i setup server with ZFS raid 10 without problem, or i stay safe to isp setup with ext4 (or xfs)?

Unfortunately i can't ask to edit hardware configuration, can't add hardware raid or other setup.

thank you

 

[Dunuin]

ZFS needs RAM. The more the better. By default ZFS will use up to 50% of your RAM for its ARC (so 1 to 16GB RAM in use case). With 4x 2TB I would atleast give ZFS 4-8 GB RAM so you wouldn't get 26GB for your VMs if you also take into account that PVE wants 1-2GB and that KVM will have overhead.

 

[ale.ab]

ok, so if i understand correctly if i would use ZFS i "reserve" 16GB for ARC and i can "use" 14GB for VM... correct?

otherwise if i want use 26GB for my VM i have only one choice , i must use ext4 or xfs correct?

thank you

 

[Dunuin]

It will only reserve 1GB for ARC but likes to use more and will use up to 16GB by default. And you don't want go to small sith your ARC because the storage will get slow. So if you don't want to sacrifice some GBs of RAM for ZFS I would use something else like mdadm with xfs.

 

[ale.ab]

ok thank you for reply.

ok , so for this server ZFS is not good choiche i understand...

now i'm focusing on xfs (is better than ext4?)
and is better setup with proxmox iso so i create LVM?
i don't know why my isp default setup is without LVM....

thank you in advance

 

[Dunuin]

If you want to use the Proxmox ISO ZFS is your only choice of software raid. With PVE ontop of Debian you could also you mdadm.

 

[ale.ab]

sorry for ask again, but i'm not comfortable with install pve ontop of debian...

if i move some VM can i use this server with 32GB RAM with ZFS?
i try to search better with ZFS and found "Limit ZFS Memory Usage"
https://forum.proxmox.com/threads/ram-full.76067/
https://pve.proxmox.com/wiki/ZFS_on_Linux

so i don't want performance, but stable system.
so if ZFS work like xfs (or little better) for me is ok.

if my VM use 20GB total, can i setup
/etc/modprobe.d/zfs.conf
options zfs zfs_arc_max=8589934592

so i have
20 GB VM
8 GB zfs arc
3/4 GB for hypervisor and other

is a stable system?

thank you again

 

[Dunuin]

Don't forget the virtualization overhead. If you got 20GB RAM assigned to VMs that might use 22-24GB RAM because of the KVM overhead. Then you want atleast 2GB for your PVE. If you don't want great performance ZFS should run fine with just 4GB RAM. So I guess 20GB RAM to VMs should work.