3 ms·
Is filesystem-level checksums better than dm-integrity which works at the block level?
by FooBarWidget 4y ago
Is filesystem-level checksums better than dm-integrity which works at the block level?
- greenicon 4y agoWith dm-integrity you either have a small hole of a few milliseconds (bitmap mode) or write all data twice (journal mode). When integrating everything into a cow file system you can sidestep the issue, as you basically journal the data through cow anyway.
- viraptor 4y agoThe only small advantage I can think of is that the filesystem knows which parts of the drive are being used, so it will not try to recover stale/unused blocks. Same goes for writing - dm-integrity needs to initialise the whole drive and update every single write, but the fs can issue some big TRIMs instead. (Or does integrity know how to trim these days? (Apparently it depends on the usage mode https://www.kernel.org/doc/html/latest/admin-guide/device-mapper/dm-integrity.html https://www.kernel.org/doc/html/latest/admin-guide/device-ma...))