[fpoling]

lvm only supports checksums for metadata. It does not checksum the data itself. For checksums with arbitrary filesystems one can have dm-integrity device rather than LVM. But the performance suffer due to separated journal writes by the device.

[phoronixrly]

I said lvmraid[1][2].

[1] https://www.man7.org/linux/man-pages/man7/lvmraid.7.html#DAT...

[2] https://docs.redhat.com/en/documentation/red_hat_enterprise_...

[fpoling]

But that is just raid on top of dm-integrity. And Redhat docs omits an important part when suggesting to use the bitmap mode with dm-integrity:

man 8 integritysetup:

       --integrity-bitmap-mode. -B
           Use alternate bitmap mode (available since Linux kernel 5.2) where dm-integrity uses bitmap instead of a journal. If a bit in the bitmap is 1, then corresponding region’s data and integrity tags are not synchronized - if the machine crashes, the unsynchronized regions will be recalculated. The bitmap mode is faster than the journal mode, because we don’t have to write the data twice, but it is also less reliable, because if data corruption happens when the machine crashes, it may not be detected.

I just do not see how without a direct filesystem support one can have both reliable checksums and performance.

[phoronixrly]

> But that is just raid on top of dm-integrity

As I said -- boring tech. Just what I like when not in a mood to lose data.