On Sun, 27 Nov 2022 14:33:37 +0000 Wol <antlists@xxxxxxxxxxxxxxx> wrote: > If raid supports trim, that means it intercepts the trim commands, and > uses it to keep track of what's being used by the layer above. > > In other words, if the filesystem is only using 10% of the disk, > supporting trim means that raid knows which 10% is being used and only > bothers syncing that! Not sure which RAID system you are speaking of, but that's not presently implemented in mdadm RAID. It does not use TRIM of the array to keep track of unused areas on the underlying devices, to skip those during rebuilds. And I am unaware of any other RAID that does. Would be nice to have though. -- With respect, Roman
