How to Mirror the Root (/) File System
Use this procedure to mirror the root (/) file system.
Steps
-
Become superuser on the node.
-
Place the root slice in a single-slice (one-way) concatenation.
Specify the physical disk name of the root-disk slice (cNtXdY sZ).
# metainit -f submirror1 1 1 root-disk-slice
-
Create a second concatenation.
# metainit submirror2 1 1 submirror-disk-slice
-
Create a one-way mirror with one submirror.
# metainit mirror -m submirror1
Note –If the device is a local device to be used to mount a global-devices file system, /global/.devices/node@nodeid, the metadevice or volume name for the mirror must be unique throughout the cluster.
-
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
-
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
-
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
-
Reboot the node.
This command remounts the newly mirrored root (/) file system.
# shutdown -g0 -y -i6
-
Use the metattach(1M) command to attach the second submirror to the mirror.
# metattach mirror submirror2
-
If the disk that is used to mirror the root disk 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 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.
-
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
-
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 …
-
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
-
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.
-
-
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 Chapter 7, Troubleshooting the System, in Solstice DiskSuite 4.2.1 User’s Guide, Special Considerations for Mirroring root (/) in Solaris Volume Manager Administration Guide, or Creating a RAID-1 Volume in Solaris Volume Manager Administration Guide for more information about alternate boot devices.
# ls -l /dev/rdsk/root-disk-slice
-
Repeat Step 1 through Step 11 on each remaining node of the cluster.
Ensure that each metadevice or volume name for a mirror on which a global-devices file system, /global/.devices/node@nodeid, is to be mounted is unique throughout the cluster.
Example 3–2 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. Device c2t2d0 is a multihost 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 |
Next Steps
To mirror the global namespace, /global/.devices/node@nodeid, go to How to Mirror the Global Namespace.
To mirror file systems than cannot be unmounted, go to How to Mirror File Systems Other Than Root (/) That Cannot Be Unmounted.
To mirror user-defined file systems, go to How to Mirror File Systems That Can Be Unmounted.
Otherwise, go to Creating Disk Sets in a Cluster to create a disk set.
Troubleshooting
Some of the steps in this mirroring procedure might cause an error message similar to metainit: dg-schost-1: d1s0: not a metadevice. Such an error message is harmless and can be ignored.
- © 2010, Oracle Corporation and/or its affiliates