> Moving a resource from one cachet to the other will be a rare event > (maintenance, patch, test, crash)
The crash aspect of this needs more investigation IMO. So there are ways to forcibly turn on a backing disk even if it's cache device is gone (because it's now running on the other head-unit). In write-thru at least you hope the written data is there (modulo caching further up the stack like in the application, or linux filesystem, or downstream at the HBA and on-disk caches). Once the crashed head is booted you'll need to invalidate all associations still present in the cache device. I don't see how you can "echo <CSET-UUID> > /sys/block/bcache0/bcache/dettach" when 'bcache0' doesn't exist anymore on that head. so now we've got no way to clean up the cacheset except to blow it away and re-init with 'make-bcache -C <ssd>' or do we accomplish the same thing by 'echo unregister > /sys/fs/bcache/<cset-uuid>/bdev'? -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
