Chris Mason <[EMAIL PROTECTED]> writes: Just commenting on something that tripped me while reading the document.
>If Btrfs were to rely on device mapper or MD for mirroring, it would >not be able to resolve checksum failures by checking the mirrored >copy. The lower layers don't know the checksum or granularity of the >filesystem blocks, and so they are not able to verify the data they >return. I cannot imagine it would be that difficult to add a new READ_OTHER_COPY io operation that would cause MD/LVM/... to return the other copy in a mirror set. Even without btrfs that might be even generally useful for other applications that do some checking on their files. e.g. I could well imagine a new system call to trigger this on the page cache level. There might be other reasons to reinvent another storage manager of course. Just that one above doesn't seem to be very convincing. I admit I haven't thought too deeply about the other issues you raise in the document. -Andi _______________________________________________ Btrfs-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/btrfs-devel
