Neil Brown (neilb@xxxxxxx) said: > Yes, I have not been thinking much about the shutdown side of the equation. > Cleanup isn't an issue - you do not need to clean up /var/run when shutting > down because it always happens on boot (and won't happen on a crash anyway). > The only possible issue that I can see is if you want to unmount /var before > setting / to read-only. You won't be able to do this because mdmon holds an > open file descriptor on /var. > So instead of unmounting /var you would need to remount it read-only, and > then remount '/' read-only. > > Is that going to be a problem? It's certainly a change in behavior. Historically all non-root filesystems can be cleanly unmounted, then root is marked read-only, then you halt/reboot. > The first is as a cache for the mapping from UUID to md device (major/minor > number). This is particularly need for Incremental mode so that when a new > device is found, it is easy to find if an md device already is (partially) > assembled for that array. > Being a cache, this information can be recreated at any time - simply read > the meta from some device in each array in record the UUID. This can be > done with > mdadm --incremental --rebuild-map > (or mdadm -Ir). > I think "mdadm --incremental" might even do this transparently if the mapfile > cannot be found. This seems like it could be integrated with the udev database, could it not? (Whether or not you want this dependency is another matter.) > 3/ Document that at mdmon may prevent /var from being unmounted and > recommend "-o remount,ro" as an alternative. As said above, I think this is a problem. Bill -- 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
