Help an old windows guy to get his head around Proxmox storage

[bawjaws]

Hiya!

I have spent years working with Windows and I'm new to Proxmox, althought I have some experience with Linux running in Virtualbox on Windows.

In Windows, the C drive is the system drive, so it makes sense for this to be as fast as possible - hence the use of NVMe M.2 storage for OS and application things, with HDD/SSDs for data storage. When running Linux in Virtualbox, the VM system files would also be saved to the local NVMe drive, and you could access the data drives as SMB shares and mount them in Linux.

This doesn't seem to work the same way in Proxmox. Proxmox has been installed onto the NVMe drive, but when I go to create VMs, it wants to store those VM files on the slower HDDs (which are running as a mirrored ZFS pool). Is this best practice? I had ordered a new (larger) NVMe drive thinking that I'd need extra storage to store the VM system files, but if they're going to be stored in the ZFS pool, maybe the existing 128GB NVMe will be sufficient.

Thanks!
K

 

[leesteken]

The Proxmox installation does not need much space and it does not have to be fast, but it does write a lot of logs and statistics. A mirror of HDDs would be fine and probably have lots of space left for ISO's etc., and probably work better than using consumer SSDs.
The VMs are going to put multiple systems worth of I/O-operations on their storage. Best to use enterprise SSDs (with PLP to cache sync writes) because they can handle the high number of IOPS and writes with good performance.

 

[aaron]

In general, Proxmox VE makes use of the features provided by the storage type. Depending on the storage type, disk images will not always be stored as files. This is because many storage types (LVM, ZFS, RBD, …) offer direct block devices that can be mapped directly into the VM as disk image.
In these situations, you will have to use the tools for the specific storage type.

For ZFS, you can for example run zfs list. For anything in an LVM: lvs to list the disk images.

If you need to interact with them directly, they are usually exposed some way or another in the /dev directory.

For ZFS for example, you should have a path /dev/zvol/{pool}/{optional sub datasets}/{disk image}. Logical Volumes in an LVM are mapped for example in /dev/mapper.

The installer will create a first storage for VM disks which is either called "local-lvm" or "local-zfs". These are located on the installation disk. You can then add more disks and create new storage either via the GUI or manually. The latter allows for more complicated ZFS pools for example. But then you need to add the storage configuration (Datacenter->Storage) yourself, so Proxmox VE knows about it.

I hope that helps