Feature Request - Support For thin provisioned block storage (iSCSI, FC... /SAN)

[nagilum99]

While XenServer got it's proprietary GFS2, XCP-ng still lack the option of a thin-provisioned, modern, block storage.
Many storage systems are connected via iSCSI or (probably lest often than iSCSI) Fibre Channel.

The current LVM/VHD-combo currently still lacks of:

• 2 TB limit
• Thin provisioning (effiicient space usage)
• Snapshots using TP (effiicient space usage and enabling big VMs to be snapshooted, migrated etc)

Due to performance reasons it was less of a thing with pure HDD storages, as it can easily end up in lots of fragments, but due to a steady increase of hybrid or even full-flash storages, it's barely a point anymore.

Still something to cach up with VMware and (now back) XenServer.

[olivierlambert]

Hi,

The GFS2 SR from XenServer is not production ready: it's based on SMAPIv3, without support for any migration path from SMAPIv1, no live storage migration, no backup/delta capability and so on.

But we have plans on our side: improving SMAPIv3 and build a driver for a shared block based. Maybe GFS2 is an option, maybe not.

[nagilum99]

Is there any schedule for that? Even a rough one?

[olivierlambert]

First, getting one SMAPIv3 local driver available (matter of weeks now), then backup capabilities, then a migration path, then shared file based SR (NFS) and finally shared block (the hardest thing). No ETA because depends on previous steps.

[gfac4hub]

I see that this was discussed about 7 months ago. As you know, support for block storage on fibre channel and elimination of 2 TB limits would be a huge deal in supplanting other vendors dominance in the enterprise marketplace. I just wanted to check how things are going in moving towards this feature?

[rave-net]

I'm working on submitting some code as this is high priority for me as well. Hoping I've thought this through properly. Anyone willing to test in an obviously non-production environment? Should have my branch ready next week.

[gfac4hub]

Please post when you get something ready with some details on the implementation and testing so far.

[stormi]

How do you handle locks and synchronization between hosts? That's the main challenge with shared block storage.