storage configuration lvm vs lvm-thin

[Netsons]

Hello,
i have few questions for you. I am trying to find answers on your docs but no way.

- We had 2 different hypervisor: one with a datastore of 10TB and another with datastore of 50TB. We expect to fill in all space inside datastores. Do you suggest creating them with lvm or lvm-thin given metadata limitation of 16GB ?

- I read that metadata content contains also snapshots and clones information. Do you think that with many operation like migration or similar we fill in all metadata space ?

- When I remove a vm from a datastore, all metadata information about this vm will be removed from metadata device(lvm-thin) ?

- I see that pve use lvm-thin by default. Do you plan to support "LVM classic" in future release or just lvm-thin ?


Waiting for your reply

Best regards

 

[aaron]

Overall you will need to ask yourself what you need. Different storage backends have different features and requirements. See the documentation: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_storage_types

- We had 2 different hypervisor: one with a datastore of 10TB and another with datastore of 50TB. We expect to fill in all space inside datastores. Do you suggest creating them with lvm or lvm-thin given metadata limitation of 16GB ?

If you don't need snapshots, then a regular (think) lvm will work for sure. If you need snapshots it gets trickier. The 16G max metadata size might work, depending on how many snapshots you plan to have. An alternative could be to split up the large storage into several thin lvm pools.

I don't have any experience with such large thin pools and the metadata usage.

You could also choose another storage backend, if possible. ZFS for example should work fine, but then you want the disks passed through directly (HBA instead of a RAID controller) and create a raid 10 like pool consisting of mirror vdevs.

- When I remove a vm from a datastore, all metadata information about this vm will be removed from metadata device(lvm-thin) ?

The metadata for the VMs disks on the storage will be removed yes.

- I see that pve use lvm-thin by default. Do you plan to support "LVM classic" in future release or just lvm-thin ?

What the installer sets up as default depends on the target file system. If you choose anything else and ZFS, you will get a thin pool for the guest storage by default.

If you know that you want something else, you can change it afterwards. You can delete the storage config for the local-lvm storage and the underlying thin lvm and create whatever you want.

Another approach with a customized storage layout would be to first install Debian and create the custom storage layout during the installation and then install PVE on top. See https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_install_proxmox_ve_on_debian