Ways to clone an iSCSI backed template storage on the iSCSI provider side rather than copying ?

[coolnodje]

I'm using exclusively iSCSI storage on PVE latest.

I realized that each VM template cloning operation copies the entirety of the template Hard Disk from the iSCSI provider through the network and back to the same iSCSI provider.

There might be no standard way to trigger a volume clone using the standard iSCSI protocol, and that seems like a huge waste to me, especially as probably every SAN provider has the ability to clone at no cost with COW filesystem.

Is there a something like a framework to implement such operation on PVE ? which I suppose needs to be on a per-provider basis ...

 

[LnxBil]

Is there a something like a framework to implement such operation on PVE ? which I suppose needs to be on a per-provider basis ...

Yes and some vendors have already support for this. Yet unless the vendors provide this "glue", it will not be possible.

 

[bbgeek17]

Hi @coolnodje,

There’s no such thing as “clone” in iSCSI, nor is there snapshot, compression, zero optimization, etc.

iSCSI is a well-established (25+ years) protocol that encapsulates SCSI commands over TCP/IP. It’s a standards-based, vendor-independent way to move block data.

With any vendor, all of the “advanced” data management is handled out-of-band through some other protocol or API. That functionality happens inside the storage system itself. As @LnxBil mentioned, some vendors provide Proxmox integration (an API bridge) for this kind of management.

Regarding your assumption that “every SAN provider has the ability to clone at no cost with a COW filesystem”, that’s not always true. Not every SAN uses a filesystem internally. In fact, some vendors deliberately avoid it: while using a filesystem can be a quick path to market, it often comes with a significant performance penalty.

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[coolnodje]

Hey, thanks for your answers.

Do you have examples of such vendors integration and how it provides the "glue" for PVE to be able to handle the "advanced" data management? I'd be curious to understand how it works.

I assume https://pve.proxmox.com/wiki/Storage:_ZFS_over_ISCSI actually stands for the PVE "framework" allowing vendors implementation for the ZFS specific usecase, correct ?