Le mercredi 19 octobre 2011 à 12:45 +0200, Yann Droneaud a écrit : > Hi, > > Does lvremove, vgremove, pvremove issue discard (eg. TRIM) commands > in order to release LE/PE/metadata blocks from the underlying devices (SSD) ? > It seems the discard feature was added to LVM2 since version 2.02.85 (released on 29th April 2011), in WHATS_NEW: Add "devices/issue_discards" to lvm.conf. Issue discards on lvremove and lvreduce etc. if enabled and supported. But the documentation is unclear about it. In example.conf.in / lvm.conf.5.in: " Issue discards to a logical volumes's underlying physical volume(s) when the logical volume is no longer using the physical volumes' space (e.g. lvremove, lvreduce, etc). Discards inform the storage that a region is no longer in use. Storage that supports discards advertise the protocol specific way discards should be issued by the kernel (TRIM, UNMAP, or WRITE SAME with UNMAP bit set). Not all storage will support or benefit from discards but SSDs and thinly provisioned LUNs generally do. If set to 1, discards will only be issued if both the storage and kernel provide support. " Does it apply for the blocks holding meta data, e.g. will pvremove issue discard requests for the PV meta data ? Regards. -- Yann Droneaud _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
