LIO target doesn't support discard on thin volumes

Bug #2023168 reported by Gorka Eguileor
This bug affects 2 people
Affects Status Importance Assigned to Milestone
In Progress
Gorka Eguileor

Bug Description

Even if we set the cinder configuration option "report_discard_supported" to "true" when using the LVM driver with the LIO target and use thin provisioning, the Nova instances cannot reclaim unused space when the guest OS runs the "fstrim" command.

This is because the LIO target is not currently emulating the unmap command.

Tags: drivers lio lvm
Revision history for this message
OpenStack Infra (hudson-openstack) wrote : Fix proposed to cinder (master)

Fix proposed to branch: master

Changed in cinder:
status: New → In Progress
Changed in cinder:
importance: Undecided → Medium
Eric Harney (eharney)
tags: added: drivers
Revision history for this message
Alejandro Garcia (agarciaws) wrote :

Hi all, I was wondering if the tgt target may have a similar problem. Reviewing its code, I couldn't find such behaviour for tgt (i.e. something like the supports_discard method implemented here).

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