On Sunday April 30, bugzilla@xxxxxxxxxxxxxxxx wrote: > > What if a disk is hot added while the filesystem is mounted. And the new > disk does not support barriers but the old disks do? Or you have a mix? When a disk is added, md will write the superblock and determine if barriers are supported or not at that time. On discovering that barriers are not support, md will flag the whole array as not supporting barriers and will start rejecting barrier requests. Filesystems that I have looked at are written to cope with barriers stopping working. The first time they get a failure, they turn off their own "use barriers" flag and retry the request in a more traditional way. > > If the new disk can't be handled correctly, maybe md should refuse to add > it. That isn't necessary. NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
