Linux – Is TRIM passed through a LVM-based PV Xen domU to the underlying SSD

linuxlvmssdtrimxen

Scenario:
— Debian Xen dom0
— SSD drive setup as LVM PV/single Volume Group.
— Debian pv_ops-based domU setup on LVM logical volume.
— File system inside domU is ext4 with discard option enabled.

Question:
Will the TRIM command generated inside the domU pass through these layers and reach the physical SSD?

Best Answer

Linux supports TRIM both as a domU (through commit ed30bf317) and dom0 (through commit b3cb0d6), but only starting with the version 3.1.

Support in DeviceMapper (the kernel technology underlying LVM) is older, so it won't be the problem.