In April I did some research on why synchronous NFSv3 performance on XFS is so rotten when compared to local filesystem performance. The workload I chose to work with is tar. After taking some measurements I came to the conclusion that one of the big problems is that we're not treating the log as stable storage. By calling write_inode_now() we've written the changes to the log first and then gone and also written them out to the inode on disk. In a short discussion of this issue on the xfs-oss list it was suggested that I post the patches here for discussion. The following series is adds a 'wsync' export option to nfsd. It is intended to be used on XFS with the wsync mount option. When you already have a synchronous log there is no need to sync metadata separately. This is barely tested, YMMV, I could have this all wrong, etc, etc. Here are some very unscientific measurements taken over gigabit ethernet. # time tar -xvf /mnt2/quilt-0.47.tar > /dev/null No XFS wsync, no NFS wsync: 0m13.177s 0m13.301s 0m13.528s XFS wsync set, no NFS wsync: 0m13.019s 0m13.232s 0m13.094s XFS wsync set, NFS wsync set: 0m8.361s 0m8.400s 0m8.301s Curious to hear if this is a reasonable thing to do. Suggestions welcome. Thanks! Ben --- Ben Myers (4): Add 'wsync' export option. Add datasync argument to nfsd_sync_dir(). If 'wsync' call vfs_fsync() instead of write_inode_now(). If 'wsync' pass datasync=1 to vfs_fsync(). fs/nfsd/export.c | 1 + fs/nfsd/nfs4recover.c | 2 + fs/nfsd/vfs.c | 62 +++++++++++++++++++++++++++++++------------ fs/nfsd/vfs.h | 2 + include/linux/nfsd/export.h | 4 ++- 5 files changed, 50 insertions(+), 21 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html