[PVE-User] sparse and compression

[Andreas Herrmann]

Hi,

On 11.12.2017 15:27, Miguel González wrote:
>> Also keep in mind: A sparse volume only stays sparse if trim/discard is used!
> 
> How do I use trim/discard? Has this to be set in guest level, right?

https://pve.proxmox.com/wiki/Qemu_trim/discard_and_virtio_scsi

>> volblocksize is important: ZFS is using 8k as default. For ZFS filesystem a
>> recordsize of 128K is used.
> 
> Can I change recordsize to 128K after creation or do I need to create a
> new zpool for that?

Play and learn:

zfs set volblocksize=16K zpool/vm-zvols/test
cannot set property for 'zpool/vm-zvols/test': 'volblocksize' is readonly

You really should read 'man zfs'

Andreas