test

Sun Cluster Software Installation Guide for Solaris OS

How to Mirror the Root (/) File System

Use this procedure to mirror the root (/) file system.

  1. Become superuser on the node.

  2. Use the metainit(1M) command to put the root slice in a single-slice (one-way) concatenation.

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


    # metainit -f submirror1 1 1 root-disk-slice

  3. Create a second concatenation.


    # metainit submirror2 1 1 submirror-disk-slice

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


    # metainit mirror -m submirror1

    Note –

    The metadevice or volume name for the mirror must be unique throughout the cluster.

  5. Run the metaroot(1M) command.

    This command edits the /etc/vfstab and /etc/system files so the system can be booted with the root (/) file system on a metadevice or volume.


    # metaroot mirror

  6. Run the lockfs(1M) command.

    This command flushes all transactions out of the log and writes the transactions to the master file system on all mounted UFS file systems.


    # lockfs -fa

  7. Move any resource groups or device groups from the node.


    # scswitch -S -h from-node
    -S

    Moves all resource groups and device groups

    -h from-node

    Specifies the name of the node from which to move resource or device groups

  8. Reboot the node.

    This command remounts the newly mirrored root (/) file system.


    # shutdown -g0 -y -i6

  9. Use the metattach(1M) command to attach the second submirror to the mirror.


    # metattach mirror submirror2

  10. Is the disk that is used to mirror the root disk physically connected to more than one node (multiported)?

    • If no, proceed to Step 11.

    • If yes, perform the following steps to enable the localonly property of the raw-disk device group for the disk used to mirror the root disk. 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(1M) -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/d2 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. Does the node list contain more than one node name?

    4. Remove all nodes from the node list for the raw-disk device group except the node whose root disk you mirrored.

      Only the node whose root disk you mirrored should remain in the node list. 


      # 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

    5. 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. Record the alternate boot path for possible future use.

    If the primary boot device fails, you can then boot from this alternate boot device. See “Troubleshooting the System” in Solstice DiskSuite 4.2.1 User's Guide or “Mirroring root (/) Special Considerations” in Solaris Volume Manager Administration Guide for more information about alternate boot devices.


    # ls -l /dev/rdsk/root-disk-slice

  12. Repeat Step 1 through Step 11 on each remaining node of the cluster.

    Ensure that each metadevice or volume name for a mirror is unique throughout the cluster.

  13. Do you intend to mirror the global namespace, /global/.devices/node@nodeid?

  14. Do you intend to mirror file systems than cannot be unmounted?

  15. Do you intend to mirror user-defined file systems?

Example—Mirroring the Root (/) File System

The following example shows the creation of mirror d0 on the node phys-schost-1, which consists of submirror d10 on partition c0t0d0s0 and submirror d20 on partition c2t2d0s0. Disk c2t2d0 is a multiported disk, so the localonly property is enabled.


(Create the mirror)
# metainit -f d10 1 1 c0t0d0s0
d11: Concat/Stripe is setup
# metainit d20 1 1 c2t2d0s0
d12: Concat/Stripe is setup
# metainit d0 -m d10
d10: Mirror is setup
# metaroot d0
# lockfs -fa
 
(Move resource groups and device groups from phys-schost-1)
# scswitch -S -h phys-schost-1
 
(Reboot the node)
# shutdown -g0 -y -i6
 
(Attach the second submirror)
# metattach d0 d20
d0: Submirror d20 is attached
 
(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
 
(Record the alternate boot path)
# ls -l /dev/rdsk/c2t2d0s0
lrwxrwxrwx  1 root     root          57 Apr 25 20:11 /dev/rdsk/c2t2d0s0 
–> ../../devices/node@1/pci@1f,0/pci@1/scsi@3,1/disk@2,0:a,raw