Sun Cluster Software Installation Guide for Solaris OS

How to Mirror File Systems That Can Be Unmounted

Use this procedure to mirror user-defined file systems that can be unmounted. In this procedure, the nodes do not need to be rebooted.

  1. Become superuser on a node of the cluster.

  2. Unmount the file system to mirror.

    Ensure that no processes are running on the file system.


    # umount /mount-point
    

    See the umount(1M) man page and “Mounting and Unmounting File Systems” in System Administration Guide: Basic Administration for more information.

  3. Put in a single-slice (one-way) concatenation the slice that contains a user-defined file system that can be unmounted.

    Specify the physical disk name of the disk slice (cNtXdYsZ).


    # metainit -f submirror1 1 1 diskslice
    

  4. Create a second concatenation.


    # metainit submirror2 1 1 submirror-diskslice
    

  5. Create a one-way mirror with one submirror.


    # metainit mirror -m submirror1
    


    Note –

    The metadevice or volume name for this mirror does not need to be unique throughout the cluster.


  6. Repeat Step 1 through Step 5 for each mountable file system to be mirrored.

  7. On each node, edit the /etc/vfstab file entry for each file system you mirrored.

    Replace the names in the device to mount and device to fsck columns with the mirror name.


    # vi /etc/vfstab
    #device        device        mount    FS     fsck    mount    mount
    #to mount      to fsck       point    type   pass    at boot  options
    #
    /dev/md/dsk/mirror /dev/md/rdsk/mirror /filesystem ufs 2 no global

  8. Attach the second submirror to the mirror.

    This attachment starts a synchronization of the submirrors.


    # metattach mirror submirror2
    

  9. Wait for the synchronization of the mirrors, started in Step 8, to be completed.

    Use the metastat(1M) command to view mirror status.


    # metastat mirror
    

  10. If the disk that is used to mirror the user-defined file system is physically connected to more than one node (multihosted), enable the localonly property.

    Perform the following steps to enable the localonly property of the raw-disk device group for the disk that is used to mirror the user-defined file system. You must enable the localonly property to prevent unintentional fencing of a node from its boot device if the boot device is connected to multiple nodes.

    1. If necessary, use the scdidadm -L command to display the full device-ID path name of the raw-disk device group.

      In the following example, the raw-disk device-group name dsk/d4 is part of the third column of output, which is the full device-ID path name.


      # scdidadm -L
      …
      1         phys-schost-3:/dev/rdsk/c1t1d0     /dev/did/rdsk/d2
      

    2. View the node list of the raw-disk device group.

      Output looks similar to the following.


      # scconf -pvv | grep dsk/d2
      Device group name:						dsk/d2
      …
        (dsk/d2) Device group node list:		phys-schost-1, phys-schost-3
      …

    3. If the node list contains more than one node name, remove all nodes from the node list except the node whose root disk you mirrored.

      Only the node whose root disk you mirrored should remain in the node list for the raw-disk device group.


      # scconf -r -D name=dsk/dN,nodelist=node
      
      -D name=dsk/dN

      Specifies the cluster-unique name of the raw-disk device group

      nodelist=node

      Specifies the name of the node or nodes to remove from the node list

    4. Use the scconf(1M) command to enable the localonly property.

      When the localonly property is enabled, the raw-disk device group is used exclusively by the node in its node list. This usage prevents unintentional fencing of the node from its boot device if the boot device is connected to multiple nodes.


      # scconf -c -D name=rawdisk-groupname,localonly=true
      
      -D name=rawdisk-groupname

      Specifies the name of the raw-disk device group

      For more information about the localonly property, see the scconf_dg_rawdisk(1M) man page.

  11. Mount the mirrored file system.


    # mount /mount-point
    

    See the mount(1M) man page and “Mounting and Unmounting File Systems” in System Administration Guide: Basic Administration for more information.

  12. Create a disk set.

    Go to Creating Disk Sets in a Cluster.

Example—Mirroring File Systems That Can Be Unmounted

The following example shows creation of mirror d4 to mirror /export, which resides on c0t0d0s4. Mirror d4 consists of submirror d14 on partition c0t0d0s4 and submirror d24 on partition c2t2d0s4. The /etc/vfstab file entry for /export is updated to use the mirror name d4. Device c2t2d0 is a multihost disk, so the localonly property is enabled.


(Unmount the file system)
# umount /export
 
(Create the mirror)
# metainit -f d14 1 1 c0t0d0s4
d14: Concat/Stripe is setup
# metainit d24 1 1 c2t2d0s4
d24: Concat/Stripe is setup
# metainit d4 -m d14
d4: Mirror is setup
 
(Edit the /etc/vfstab file)
# vi /etc/vfstab
#device        device        mount    FS     fsck    mount    mount
#to mount      to fsck       point    type   pass    at boot  options
#
/dev/md/dsk/d4 /dev/md/rdsk/d4 /export ufs 2 no	global
 
(Attach the second submirror)
# metattach d4 d24
d4: Submirror d24 is attached
 
(View the sync status)
# metastat d4
d4: Mirror
      Submirror 0: d14
         State: Okay
      Submirror 1: d24
         State: Resyncing
      Resync in progress: 15 % done
…
 
(Identify the device-ID name of the mirrored disk's raw-disk device group)
# scdidadm -L
…
1         phys-schost-3:/dev/rdsk/c2t2d0     /dev/did/rdsk/d2
 
(Display the device-group node list)
# scconf -pvv | grep dsk/d2
Device group name:						dsk/d2
…
  (dsk/d2) Device group node list:		phys-schost-1, phys-schost-3
…
 
(Remove phys-schost-3 from the node list)
# scconf -r -D name=dsk/d2,nodelist=phys-schost-3
 
(Enable the localonly property)
# scconf -c -D name=dsk/d2,localonly=true
 
(Mount the file system)
# mount /export