6 Replies Latest reply: Dec 3, 2012 2:36 PM by Avi Miller-Oracle RSS

    Mounting read-only LUNs using ocfs2

    Rodney_McKee
      Trying to hard mount a read-only LUN that has previously been formatted with ocfs2. Cannot find much on hard mounts and what options I need to use to get it to work.
      Any help appreciated

      Rgds
      Rodney
        • 1. Re: Mounting read-only LUNs using ocfs2
          tbrinkmann
          Hi,
          all normal mounts are hard mounts until you set "soft" as parameter.

          http://www.faqs.org/docs/linux_network/x-087-2-nfs.mountd.html

          More specific questions ?

          *T

          Edited by: tbrinkmann on Nov 29, 2012 12:55 AM
          • 2. Re: Mounting read-only LUNs using ocfs2
            Rodney_McKee
            I guess a bit more clarity was needed. Thanks for the quick response.

            I have data on iSCSI san that has been written to ocfs2 filesystems. The LUN is now at the point that for security sake it can be marked read-only on the san. The issue is when I try to mount it ocfs2 reports an i/o error as it need to write to the LUN as part of the clustering. The LUN is also a raw device maping in VMware.

            I did find this https://oss.oracle.com/osswiki/OCFS2%282f%29DesignDocs%282f%29ReadOnly.html but do not see how to make this happen.

            mount.ocfs2: I/O error on channel while mounting read-only device in clustered mode

            Edited by: Rodney_McKee on Nov 29, 2012 2:09 AM

            Edited by: Rodney_McKee on Nov 29, 2012 2:13 AM

            Edited by: Rodney_McKee on Nov 29, 2012 2:14 AM
            • 3. Re: Mounting read-only LUNs using ocfs2
              tbrinkmann
              Re,
              an I/O error ad this point means nothing :-/

              What distribution and kernel you are running ?

              Do you really need a cluster file system ?

              Packages installed ??
              #>rpm -qa | grep ocfs2

              Kernel module launched ?
              #>lsmod | grep ocfs

              ..and --> why are you using ocfs2, do you really need it ?

              RH
              #>service ocfs2 status ..

              SLES
              #>rcocfs2 status

              *T                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
              • 4. Re: Mounting read-only LUNs using ocfs2
                Rodney_McKee
                T,

                Re,
                an I/O error ad this point means nothing :-/
                I'm guessing it's pointing out the obvious but it's not gunna let the LUN mount as it cannot join the cluster, thats fine. But I'd like to mount it still.

                What distribution and kernel you are running ?
                OEL 6.3

                Do you really need a cluster file system ?
                Well yeah, we are currently NOT using the clustering capability on these particular LUNs but the plan for the future is to. We do use it's abilities elsewhere.

                Packages installed ??
                #>rpm -qa | grep ocfs2
                $ rpm -qa | grep ocfs2
                ocfs2-tools-1.8.0-10.el6.x86_64
                ocfs2-tools-devel-1.8.0-10.el6.x86_64


                Kernel module launched ?
                #>lsmod | grep ocfs
                $ lsmod | grep ocfs
                ocfs2 1093952 20
                ocfs2_dlmfs 20224 1
                ocfs2_stack_o2cb 4281 1
                ocfs2_dlm 228380 1 ocfs2_stack_o2cb
                ocfs2_nodemanager 219951 48 ocfs2,ocfs2_dlmfs,ocfs2_stack_o2cb,ocfs2_dlm
                ocfs2_stackglue 11896 3 ocfs2,ocfs2_dlmfs,ocfs2_stack_o2cb
                configfs 29244 2 ocfs2_nodemanager
                jbd2 93114 2 ocfs2,ext4


                ..and --> why are you using ocfs2, do you really need it ?
                We are planning to share LUNs between nodes as the plan is to allow several app servers access, while this is not in place it's the current plan. We are currently using ocfs2 (clustered) for our elasticsearch gateway filesystem.

                RH
                #>service ocfs2 status ..
                sudo /sbin/service ocfs2 status
                Configured OCFS2 mountpoints: .... (list of mount points)

                SLES
                #>rcocfs2 status
                • 5. Re: Mounting read-only LUNs using ocfs2
                  tbrinkmann
                  Hi,
                  sorry for the delay... It looks like you running the right software parts for running ocfs2. Resently I do not have time
                  to prove the behaivor in oL6.3 may someone else can help...

                  Additional to that please check the oracle lisence fpr ocfs2. You may need to use acfs

                  You you will come over :-/
                  *T                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
                  • 6. Re: Mounting read-only LUNs using ocfs2
                    Avi Miller-Oracle
                    Rodney_McKee wrote:
                    Trying to hard mount a read-only LUN that has previously been formatted with ocfs2. Cannot find much on hard mounts and what options I need to use to get it to work.
                    You cannot mount an OCFS2 partition that's flagged read-only on the SAN. It will always fail. OCFS2 has to be able to write journals on mount. You can mount it on local read-only mode though (-o ro).