[PVE-User] Qcow2 and raw format, disk provisioning and SSDs

[Miguel González]

Hi,

 I am migrating from a server with Proxmox 4.4-18 with SATA drives to a
Proxmox 5.1-36 with SSD drives.

 I am trying to get the best in performance. I already split OS and data
disk drives so /home folder is not being backed up by Proxmox, only OS.

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5       29G    17G  12G   58% /
tmpfs           8.3G     0  8.3G   0% /dev/shm
/dev/sdb1        50G   33G   14G  71% /home
/dev/sda1       504M  178M  301M  38% /boot
/dev/sda2       2.0G   75M  1.8G   4% /tmp

The sda drive was 250 Gb and I shrink it to 36 Gb. I have already zeroed
all sda partitions with dd but still after converting qcow2 following
this https://pve.proxmox.com/wiki/Shrink_Qcow2_Disk_Files the resulting
qcow2 file is 48 Gb, not 36-40 Gb.

Something am I missing?

On the other hand, a few more questions:

- Should I move to RAW format? Pros? Cons? I have read that backups take
longer but performance boost is better.

- Anything that I have to change in Proxmox settings when using SSD
instead of SATA?

Thanks!

Miguel