Re: question regarding caching
Austin S Hemmelgarn wrote (ao): 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. Lose data? Where you get this from? Sander -- 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
Re: question regarding caching
On 2014-01-03 03:39, Sander wrote: Austin S Hemmelgarn wrote (ao): 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. Lose data? Where you get this from? Sander Sorry, misread the documentation, thought it said destructive where it really said non-destructive. It's still a good idea to run sync before trying to clear the caches though, cause dirty objects aren't freeable. -- 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
Re: question regarding caching
Kai Krakow wrote: Aastha Mehta aasth...@gmail.com schrieb: 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. Maybe you or your distribution deployed cachefilesd and uses it for the remote fs? The FS-Cache infrastructure only applies to filesystems which opt in to using it (NFS, recent work on Ceph, etc), so mounting btrfs over a remote block device wouldn't use it at all. -- 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
Re: question regarding caching
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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
question regarding caching
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. Wishing everyone a happy new year. Thanks and regards, Aastha. -- Aastha Mehta MPI-SWS, Germany E-mail: aasth...@mpi-sws.org -- 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
Re: question regarding caching
Aastha Mehta aasth...@gmail.com schrieb: 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. Maybe you or your distribution deployed cachefilesd and uses it for the remote fs? HTH Kai -- 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
