Re: How to enable FUSE kernel cache about dentry and inode?

Keiviw <keiviw@xxxxxxx> · Tue, 6 Sep 2016 14:57:29 +0800 (CST)

Could you please tell me your glusterfs version and the mount command that you have used?? My GlusterFS version is 3.3.0, different versions may be exits different results.

At 2016-09-06 12:35:19, "Ravishankar N" <ravishankar@xxxxxxxxxx> wrote:

    That is strange. I tried the experiment
      on a volume with a million files. The client node's memory usage
      did grow, as I observed from the output of free(1) 
      http://paste.fedoraproject.org/422551/ when I did a `ls`.

      -Ravi

      On 09/02/2016 07:31 AM, Keiviw wrote:

        Exactly, I mounted the volume in a no-brick node(nodeB),
          and nodeA was the server. I have set different timeout, but
          when I excute "ls /mnt/glusterfs(about 3 million small files,
          in other words, about 3 million dentries)", the result was the
          same, memory usage in nodeB didn't change at all while nodeA's
          memory usage was changed about 4GB!

        发自 网易邮箱大师

          On
            09/02/2016 09:45, Ravishankar N
            wrote:

          On 09/02/2016 05:42 AM, Keiviw
            wrote:

            Even
              if I set the attribute-timeout and entry-timeout to
              3600s(1h), in the nodeB, it didn't cache any metadata
              because the memory usage didn't change. So I was confused
              that why did the client not cache dentries and inodes.

          If you only want to test fuse's caching, I would try
            mounting the volume on a separate machine (not on the brick
            node itself), disable all gluster performance xlators, do a
            find.|xargs stat on the mount 2 times in succession and see
            what free(1) reports the 1st and 2nd time. You could do this
            experiment with various attr/entry timeout values. Make sure
            your volume has a lot of small files.

            -Ravi

              在 2016-09-01 16:37:00，"Ravishankar N" <ravishankar@xxxxxxxxxx>
              写道：

                On 09/01/2016 01:04 PM,
                  Keiviw wrote:

                    Hi,
                        I have found that GlusterFS client(mounted
                      by FUSE) didn't cache metadata like dentries and
                      inodes. I have installed GlusterFS 3.6.0 in nodeA
                      and nodeB, and the brick1 and brick2 was in nodeA,
                      then in nodeB, I mounted the volume to
                      /mnt/glusterfs by FUSE. From my test, I excuted
                      'ls /mnt/glusterfs' in nodeB, and found that the
                      memory didn't use at all. Here are my questions:
                        1. In fuse kernel, the author set some
                      attributes to control the time-out about dentry
                      and inode, in other words, the fuse kernel
                      supports metadata cache, but in my test, dentries
                      and inodes were not cached. WHY?
                        2. Were there some options in GlusterFS
                      mounted to local to enable the metadata cache in
                      fuse kernel? 

                You can tweak the attribute-timeout and
                  entry-timeout seconds while mounting the volume.
                  Default is 1 second for both.  `man mount.glusterfs`
                  lists various mount options.

                  -Ravi

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