Diskspace vanish

[caine]

Hi!

I´m new to Proxmox, setting up my server to run three VM-servers.

Hostingserver:
8 x 3 TiB Red NAS drives
32Gb ECC
Intel 1230V5 4-core (3,4Ghz)
2 x SSD RAID 1 Proxmox boot drives.
ProxMox 5.1-43

My main storage is 8 x 3TiB RAIDZ2 = 17,5 TiB
I´ve created three VM´s - NextCloud, PlexMedia and a pure Storage server (SMB), all with Debian OS.

NextCloud (40 Gb)
PlexMedia (2 TiB)
Storage (15 TiB)

Using SMB-share to add content to my PlexMedia server, i´ve noticeing that for every 100Gb added, 200Gb vanish on my total main storage. What a heck!?!

Every VM is RAW.

Any suggestions?!





PlexMediaServer (2 TiB)

of 2.0 TiB totalt, 1,5 TiB is occupied.


But 3,1 TiB is gone on my Main storage?!!

 

[guletz]

Hi,

You must understand that you have 2 different perspective regarding storage space(zfs storage and vm storage). And zfs is cow(copy on write). So in vm you have let say a big file (1 Tb). Then you start to re-write the same file for 3 times.
From the vm perspective this file will use the same storage space. But from zfs perspectiv for each re-write of the same file will be another 1 Tb of new data. Zfs can not know more (your ext4 vm fs will not tell nothing about files to zfs layer - The fs from vm do not know nothing about zfs). The only thing you can do is to use fstrim in the VM. Trim operation from vm will tell to the zfs that you delete some disk blocks from VM, then the VM iscsi controller(check discard) will pass this info to the zfs. With this trim/discard info, zfs will delete this blocks.

 

[caine]

Thank you!! - that was the problem. Your explanation made everything logical!

 

[guletz]

... welcome to zfs world