RFC: use TRIM data from filesystems to speed up array rebuild?

Hi,

I'm not really a filesystem guy so this may be a really dumb question.

We currently have an issue where we have a ~1TB RAID1 array that is mostly given over to LVM.  If we swap one of the disks it will rebuild everything, even though we may only be using a small fraction of the space.

This got me thinking.  Has anyone given thought to using the TRIM information from filesystems to allow the RAID code to maintain a bitmask of used disk blocks and only sync the ones that are actually used?

Presumably this bitmask would itself need to be stored on the disk.

Thanks,
Chris


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Chris Friesen
Software Designer

3500 Carling Avenue
Ottawa, Ontario K2H 8E9
www.genband.com