On Thu, Sep 17, 2015 at 07:56:08PM +0200, Gert Menke wrote: > MD+LVM is very close to what I want, but md has no way to cope with silent > data corruption. So if I'd want to use a guest filesystem that has no > checksums either, I'm out of luck. > I'm honestly a bit confused here - isn't checksumming one of the most > obvious things to want in a software RAID setup? Is it a feature that might > appear in the future? Maybe I should talk to the md guys...
MD is emulating hardware RAID. In hardware RAID, you are doing work at the block level. Block-level RAID has no understanding of the filesystem(s) running on top of it. Therefore it would have to checksum groups of blocks, and store those checksums on the physical disks somewhere, perhaps by keeping some portion of the drive for itself. But then this is not very efficient, since it is maintaining checksums for data that may be useless (blocks the FS is not currently using). So then you might make the RAID filesystem aware...and you now have BTRFS RAID. Simply put, the block level is probably not an appropriate place for checksumming to occur. BTRFS can make checksumming work much more effectively and efficiently by doing it at the filesystem level. --Sean -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
