On 12/30/2013 09:24 PM, Aastha Mehta wrote: > Hello, > > I have some questions regarding caching in BTRFS. When a file > system is unmounted and mounted again, would all the previously > cached content be removed from the cache after flushing to disk? > After remounting, would the initial requests always be fetched from > the disk? > > Rather than a local disk, I have a remote device to which my IO > requests are sent and from which the data is fetched. I need > certain data to be fetched from the remote device after a remount. > But somehow I do not see any request appearing at the device. I > even tried to do drop_caches after remounting the file system, but > that does not seem to help. > > I guess my problem is not related to BTRFS, but since I am working > with BTRFS, I wanted to ask here for help. Could any one tell me > how I can ensure that requests are fetched from the (remote) > device, especially after file system remount, without having to > use drop_caches? > > Please let me know if I described the problem too vaguely and > should give some more details. The data is probably still cached in the block layer, so after unmounting, you could try 'echo 1 > /proc/sys/vm/drop_caches' before mounting again, but make sure to run sync right before doing that, otherwise you might lose data. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
