How to Create a RAID-1 Volume From Unused Slices
This procedure shows you how to create a two-way mirror. If you want to create a three-way mirror or a four-way mirror, use the same procedure.
Check Prerequisites for Creating Solaris Volume Manager Components and Creating and Maintaining RAID-1 Volumes.
Create two stripes or concatenations. These components become the submirrors.
See How to Create a RAID-0 (Stripe) Volume or How to Create a RAID-0 (Concatenation) Volume.
To create the mirror, use one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume and follow the onscreen instructions. For more information, see the online help.
Use the following form of the metainit command to create a one-way mirror:
# metainit volume-name -m submirror-name
volume-name
Specifies the name of the volume to create
m
Specifies to create a mirror
submirror-name
Specifies the name of the component that will be the first submirror in the mirror
See the following examples and the metainit ( 1M ) man page for more information.
To add the second submirror, use one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose the mirror you want to modify. Choose Action⇒Properties, then the Submirrors. Follow the onscreen instructions to attach the submirror. For more information, see the online help.
Use the following form of the metattach command:
# metattach volume-name submirror-name
volume-name
Specifies the name of the RAID-1 volume on which to add the submirror
submirror-name
Specifies the name of the component that will be the second submirror attached to the mirror
See the following examples and the metattach ( 1M ) man page for more information.
Example 11.1. Creating a Two-Way Mirror
#metainit d51 1 1 c0t0d0s2d51: Concat/Stripe is setup #metainit d52 1 1 c1t0d0s2d52: Concat/Stripe is setup #metainit d50 -m d51d50: Mirror is setup #metattach d50 d52d50: Submirror d52 is attached
This example shows you how to create the two-way mirror, d50.
The metainit command creates two submirrors (d51 and d52), which are RAID-0 volumes. The metainit
m command creates the one-way mirror from the d51 RAID-0
volume. The metattach command attaches d52,
creating a two-way mirror and causing a resynchronization. Any data on the
attached submirror is overwritten by the other submirror during the resynchronization.
Example 11.2. Creating a Two-Way Mirror Without Resynchronization
#metainit d51 1 1 c0t0d0s2d51: Concat/Stripe is setup #metainit d52 1 1 c1t0d0s2d52: Concat/Stripe is setup #metainit d50 -m d51 d52metainit: d50: WARNING: This form of metainit is not recommended. The submirrors may not have the same data. Please see ERRORS in metainit(1M) for additional information. d50: Mirror is setup
This example shows the creation a two-way mirror, d50.
The metainit command creates two submirrors (d51 and d52), which are RAID-0 volumes. The metainit
m command is then run with both submirrors to create the mirror.
When you create a mirror using the metainit command rather
than the metattach command , no resynchronization operations
occur. As a result, data could become corrupted when Solaris Volume Manager assumes
that both sides of the mirror are identical and can be used interchangeably.
How to Create a RAID-1 Volume From a File System
Use this procedure to mirror an existing file system. If the file system
can be unmounted, the entire procedure can be completed without a reboot.
For file systems that cannot be unmounted, such as /usr and /swap, the system must be rebooted to complete the procedure.
When creating a RAID-1 volume from an existing file system built on a slice, only the single slice may be included in the primary RAID-0 volume (submirror). If you are mirroring system-critical file systems, all submirrors must consist of only a single slice.
For the procedures associated with mirroring the root (/) file system,
see
How to Create a RAID-1 Volume From the root (/) File System and
How to Create a RAID-1 Volume From the root (/) File System.
In the example used in this procedure, the existing slice is c1t0d0s0. The second slice, c1t1d0s0, is available
for the second half of the mirror. The submirrors are d1 and d2, respectively, and the mirror is d0.
Be sure to create a one-way mirror with the metainit command then attach the additional submirrors with the metattach command. When the metattach command is not used, no resynchronization operations occur. As a result, data could become corrupted when Solaris Volume Manager assumes that both sides of the mirror are identical and can be used interchangeably.
Check Prerequisites for Creating Solaris Volume Manager Components and Creating and Maintaining RAID-1 Volumes.
Identify the slice that contains the
existing file system to be mirrored This example uses the slice c1t0d0s0.
Create a new RAID-0 volume on the slice from the previous step by using one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions . For more information, see the online help.
Use the following form of the metainit command:
# metainit -f volume-name number-of-stripes components-per-stripe component-name
f
Forces the command to continue. You must use this option when the slice contains a mounted file system.
volume-name
Specifies the name of the volume to create. For information on naming volumes, see Volume Names.
number-of-stripes
Specifies the number of stripes to create.
components-per-stripe
Specifies the number of components each stripe should have.
component-names
Specifies the names of the components that are used. This
example uses the root slice, c0t0d0s0.
Create a second RAID-0 volume (concatenation)
on an unused slice (c1t1d0s0 in this example) to act as
the second submirror. The second submirror must be the same size as the original
submirror or larger. Use one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action->Create Volume and follow the instructions on screen. For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name number-of-stripes components-per-stripe component-name
See Step 2 for an explanation of the options.
Create a one-way mirror by using one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions . For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name -m submirror-name
volume-name
Specifies the name of the volume to create.
m
Specifies to create a mirror.
submirror-name
Specifies the name of the component that will be the first submirror in the mirror. In this example, it is the RAID-0 volume that contains the root slice.
See the metainit ( 1M ) man page for more information.
When you create a mirror from an existing file system, you must follow the next two steps precisely to avoid data corruption.
Edit the /etc/vfstab file so that the file
system mount instructions refer to the mirror, not to the block device. For
more information about the/etc/vfstab file, see
Mounting
File Systems in System Administration
Guide: Devices and File Systems
.
For example,
if the /etc/vfstab file contains the following entry
for the file system:
/dev/dsk/slice/dev/rdsk/slice/var ufs 2 yes -
Change the entry to read as follows:
/dev/md/dsk/mirror-name/dev/md/rdsk/mirror-name/var ufs 2 yes -
Remount your newly mirrored file system according to one of the following procedures:
If you are mirroring a file system that can be unmounted, then unmount and remount the file system.
#umount#/filesystemmount/filesystem
If you are mirroring a file system that cannot be unmounted, then reboot your system.
# reboot
Use the following form of the metattach command to attach the second submirror.
# metattach volume-name submirror-name
volume-name
Specifies the name of the RAID-1 volume on which to add the submirror
submirror-name
Specifies the name of the component that will be the second submirror attached to the mirror
See the metattach ( 1M ) man page for more information.
Example 11.3. Creating a Two-Way Mirror From a File System That Can Be Unmounted
#metainit -f d1 1 1 c1t0d0s0d1: Concat/Stripe is setup #metainit d2 1 1 c1t1d0s0d2: Concat/Stripe is setup #metainit d0 -m d1d0: Mirror is setup #umount /master(Edit the /etc/vfstab file so that the file system references the mirror) #mount /master#metattach d0 d2d0: Submirror d2 is attached
In this example, the
f option forces the creation
of the first concatenation, d1, which contains the mounted
file system /master on /dev/dsk/c1t0d0s0.
The second concatenation, d2, is created from /dev/dsk/c1t1d0s0. This slice must be the same size as , or larger than the size
of d1.) The metainit command with
the
m option creates the one-way mirror, d0,
from d1.
Next, the entry for the file system should be changed in the /etc/vfstab file to reference the mirror. The following line in the /etc/vfstab file initially appears as follows:
/dev/dsk/c1t0d0s0 /dev/rdsk/c1t0d0s0 /var ufs 2 yes -
The entry is changed to the following:
/dev/md/dsk/d0 /dev/md/rdsk/d0 /var ufs 2 yes -
Finally, the file system is remounted and submirror d2 is
attached to the mirror, causing a mirror resynchronization. The system confirms
that the RAID-0 and RAID-1 volumes are set up, and that submirror d2 is
attached.
Example 11.4. Creating a Two-way Mirror From a File System That Cannot Be Unmounted
#metainit -f d12 1 1 c0t3d0s6d12: Concat/Stripe is setup #metainit d22 1 1 c1t0d0s6d22: Concat/Stripe is setup #metainit d2 -m d12d2: Mirror is setup (Edit the /etc/vfstab file so that /usr references the mirror) #reboot... #metattach d2 d22d2: Submirror d22 is attached
This example creates a two-way mirror using a slice containing the /usr file system. The
f option forces the creation
of the first concatenation, d12, which contains the mounted
file system /usr on /dev/dsk/c0t3d0s6.
The second concatenation, d22, is created from /dev/dsk/c1t0d0s6. This slice must be the same size as, or larger than the size
of d12. The metainit command with
the
m option creates the one-way mirror d2 using
the concatenation that contains the /usr file system.
Next, the /etc/vfstab file must be edited to change the
entry for /usr to reference the mirror.
The /etc/vfstab file contains the following entry
for the /usr file system:
/dev/dsk/c0t3d0s6 /dev/rdsk/c0t3d0s6 /usr ufs 1 yes -
Change the entry to read as follows:
/dev/md/dsk/d2 /dev/md/rdsk/d2 /usr ufs 1 yes -
After a reboot, the second submirror d22 is
attached to the mirror, causing a mirror resynchronization.
Example 11.5. Creating a Mirror From the /swap Space
#metainit -f d11 1 1 c0t0d0s1d11: Concat/Stripe is setup #metainit d21 1 1 c1t0d0s1d21: Concat/Stripe is setup #metainit d1 -m d11d1: Mirror is setup (Edit the /etc/vfstab file so that swap references the mirror) #reboot... #metattach d1 d21d1: Submirror d21 is attached
In this example, the
f option forces the creation of
the first concatenation, d11, which contains the mounted
file system swap on /dev/dsk/c0t0d0s1.
The second concatenation, d21, is created from /dev/dsk/c1t0d0s1. This slice must be the same size as, or larger than the size
of d11. The metainit command with
the
m option creates the one-way mirror d1 using
the concatenation that contains swap. Next, if there
is an entry for swap in the /etc/vfstab file,
it must be edited to reference the mirror.
The /etc/vfstab file contains the following entry
for the swap space:
/dev/dsk/c0t0d0s1 - - swap - no -
Change the entry to read as follows:
/dev/md/dsk/d1 - - swap - no -
After a reboot, the second submirror d21 is attached
to the mirror, causing a mirror resynchronization.
To save the crash dump when you have mirrored the swap space,
use the dumpadm command to configure the dump device as
a volume. For instance, if the swap device is named /dev/md/dsk/d2,
use the dumpadm command to set this device as the dump
device.
How to Create a RAID-1 Volume From the
root (/) File System
The process for mirroring the root (/) file system
on a SPARC platform is similar to mirroring any other file system that you
cannot unmount. The procedure differs in that the metaroot command
is run instead of manually editing the /etc/vfstab file.
Mirroring the root (/) file system also requires recording
the path to the alternate boot device. This device reboots the system if the
submirror fails.
In the example used in this procedure, the existing slice is c1t0d0s0. The second slice, c1t1d0s0, is available
for the second half of the mirror. The submirrors are d1 and d2, respectively, and the mirror is d0.
Be sure to create a one-way mirror with the metainit command then attach the additional submirrors with the metattach command. When the metattach command is not used, no resynchronization operations occur. As a result, data could become corrupted when Solaris Volume Manager assumes that both sides of the mirror are identical and can be used interchangeably.
Check Prerequisites for Creating Solaris Volume Manager Components and Creating and Maintaining RAID-1 Volumes.
Identify the slice that contains the existing root (/)
file system to be mirrored. This example uses the slice c1t0d0s0.
Create a new RAID-0 volume on the slice from the previous step by using one of the following methods. Only the single slice can be included in the RAID-0 volume.
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions . For more information, see the online help.
Use the following form of the metainit command:
# metainit -f volume-name number-of-stripes components-per-stripe component-name
f
Forces the command to continue. You must use this option when the slice contains a mounted file system.
volume-name
Specifies the name of the volume to create. For information on naming volumes, see Volume Names.
number-of-stripes
Specifies the number of stripes to create.
components-per-stripe
Specifies the number of components each stripe should have.
component-names
Specifies the names of the components that are used. This
example uses the root slice, c0t0d0s0.
Create a second RAID-0 volume on an unused slice (c1t1d0s0 in
this example) to act as the second submirror. The secondary submirror must
be the same size as the original submirror, or larger. Use one of the following
methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action->Create Volume and follow the instructions on screen. For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name number-of-stripes components-per-stripe component-name
See Step 2 for and explanation of the options.
Create a one-way mirror by using one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions . For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name -m submirror-name
volume-name
Specifies the name of the volume to create.
m
Specifies to create a mirror.
submirror-name
Specifies the name of the component that will be the first submirror in the mirror. In this example, it is the RAID-0 volume that contains the root slice.
Remount your newly mirrored file system. Run the metaroot volume-name
command, replacing volume-name with
the name of the mirror you have created. Then, reboot your system.
#metaroot#volume-namereboot
For more information, see the metaroot ( 1M ) man page.
Use the following form of the metattach command to attach the second submirror.
# metattach volume-name submirror-name
volume-name
Specifies the name of the RAID-1 volume on which to add the submirror
submirror-name
Specifies the name of the component that will be the second submirror attached to the mirror
See the metattach ( 1M ) man page for more information.
Record the alternate boot path.
Determine the path to the alternate root device. Use the ls
l
command on the slice that is being attached as the second
submirror to the root (/) file system mirror.
# ls -l /dev/dsk/c1t1d0s0
lrwxrwxrwx 1 root root 55 Mar 5 12:54 /dev/rdsk/c1t1d0s0 -> \
../../devices/sbus@1,f8000000/esp@1,200000/sd@3,0:a
Record the string that follows the /devices directory: /sbus@1,f8000000/esp@1,200000/sd@3,0:a.
Because the system might not be available, this information should also be written down somewhere other than on the system. See Recovering From Boot Problems for details on booting from the alternate boot device.
Edit the string to change the major name (sd,
in this case) to disk, resulting in /sbus@1,f8000000/esp@1,200000/disk@3,0:a. If the system uses an IDE bus, the original full path might look
like
$ ls -l /dev/dsk/c1t1d0s0
lrwxrwxrwx 1 root root 38 Mar 13 15:03 /dev/dsk/c0t0d0s0 -> \
../../devices/pci@1f,0/ide@d/dad@0,0:a
After changing the major name dad to disk,
you would have /pci@1f,0/ide@d/disk@0,0:a
Use the OpenBoot™ PROM nvalias command
to define a “backup root” device alias for the secondary root
(/) file system mirror. For example:
ok nvalias backup_root /sbus@1,f8000000/esp@1,200000/disk@3,0:a
Redefine the boot-device alias to reference
both the primary and secondary submirrors, in the order in which you want
them to be used, and store the configuration.
okprintenv boot-deviceboot-device = disk net oksetenv boot-device disk backup_root netboot-device = disk backup_root net oknvstore
In the event that the primary submirror fails, the system would automatically boot to the second submirror. Or, if you boot manually, rather than using autoboot, you would enter:
ok boot backup_root
Example 11.6. SPARC: Creating a Mirror From the root (/) File
System
#metainit -f d1 1 1 c0t0d0s0d1: Concat/Stripe is setup #metainit d2 1 1 c0t1d0s0d2: Concat/Stripe is setup #metainit d0 -m d1d0: Mirror is setup #metaroot d0#lockfs -fa#reboot... #metattach d0 d2d0: Submirror d2 is attached #ls -l /dev/dsk/c0t1d0s0lrwxrwxrwx 1 root root 88 Feb 8 15:51 /dev/rdsk/c1t3d0s0 -> ../../devices/pci@1f,0/pci@1,1/ide@3/dad@0,0:a #init 0. . . oknvalias backup_root /pci@1f,0/pci@1,1/ide@3/disk@0,0:aoksetenv boot-device disk backup_root netoknvstore
In this example, the
f option forces the creation of
the first RAID-0 volume, d1, which contains the mounted
root (/) file system on /dev/dsk/c0t0d0s0.
The second concatenation, d2, is created from /dev/dsk/c0t1d0s0. This slice must be the same size as, or larger than the size
of d1. The metainit command with the
m option creates the one-way mirror d0 using
the concatenation that contains root (/).
Next, the metaroot command edits the /etc/vfstab and /etc/system files so that the system
can be booted with the root (/) file system on a volume.
It is a good idea to run the lockfs
fa
command
before rebooting. For more information, see the
lockfs
(
1M
)
man page.
Do not attach the second submirror before the system is rebooted. You must reboot after running the metaroot command and before attaching the second submirror.
After a reboot, the submirror d2 is attached to
the mirror, causing a mirror resynchronization. The system confirms that the
concatenations and the mirror are set up, and that submirror d2 is
attached.
The ls
l
command is run on the root
raw device to determine the path to the alternate root device in case the
system might later need to be booted from it.
How to Create a RAID-1 Volume From the root (/) File System
The process for mirroring the root (/) file system
on an x86 based system is similar to mirroring root on a SPARC system.
However, on x86 based systems, the BIOS and fdisk partitioning
add an additional layer of complexity.
In the example used in the procedures, the existing slice is c1t0d0s0. The second slice, c1t1d0s0, is available
for the second half of the mirror. The submirrors are d1 and d2, respectively, and the mirror is d0.
Before implementing any of the procedures, check Prerequisites for Creating Solaris Volume Manager Components and Creating and Maintaining RAID-1 Volumes.
Verify that the ordering for the BIOS boot device can be configured to allow the system to boot off of the second disk in the mirror.
Before the kernel is started, the system is controlled by the read-only-memory (ROM) Basic Input/Output System (BIOS), which is the firmware interface on an x86 based system. The BIOS is analogous to the boot PROM on a SPARC based system. Some of the BIOS's tasks are as follows:
Perform startup functions.
Detect the correct device from which to boot the system.
Load the master boot record from that device to allow the system to self-boot.
You can usually configure the BIOS to select the order of devices to probe for the boot record. Additionally, most modern BIOS implementations allow you to configure your devices so that the failover to the secondary submirror is automatic. If your system's BIOS does not have this feature and the primary submirror fails, you need to access the BIOS during system boot to reconfigure the system to boot from the secondary root slice. Consult the user's guide for your BIOS for instructions on how to configure settings in your BIOS
Before setting up a root mirror, check the BIOS on your system to verify that you can boot off of more than one disk. Some device drivers are configured to only see one disk on the system.
Verify that the fdisk partitions are configured
to support root mirroring.
The existence of a separate x86 boot
partition presents a problem when mirroring the root (/)
file system. Because it exists outside of the Solaris fdisk partition,
the x86 boot partition cannot be mirrored by Solaris Volume Manager. Additionally,
because only one copy of the x86 boot partition exists, it represents a
single point of failure.
The GRUB-based installation program of the Solaris 10 1/06 software and subsequent releases no longer automatically creates an x86 boot partition. However, if the x86 already exists in the system, the installation program preserves that partition by default.
To determine if your system has a separate x86 boot partition, check
the /etc/vfstab file. The x86 boot partition exists
if the file contains an entry similar to the following:
/dev/dsk/c2t1d0p0:boot - /boot pcfs - no -
To use the Solaris Volume Manager to mirror the root (/)
file system, the file system must use the single Solaris fdisk partition.
Therefore, if the x86 boot partition already exists in the system, delete
this partition with the fdisk command and then reinstall
the Solaris software. When you reinstall, the boot partition is no longer
recreated.
Solaris Volume Manager can only mirror slices within the Solaris fdisk partition If you have multiple fdisk partitions,
you need to use another approach to protect the data outside of the Solaris fdisk partition.
Make the secondary submirror bootable with a master boot program.
Specify the master boot program.
# fdisk -b /usr/lib/fs/ufs/mboot /dev/rdsk/c1t1d0p0
The following screen appears:
Total disk size is 31035 cylinders
Cylinder size is 1146 (512 byte) blocks
Cylinders
Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===
1 Active Solaris 1 31034 31034 100
SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection:
Choose number 5 from the menu, and press return.
Make the secondary disk bootable.
# /sbin/installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t1d0s0
For more information about installgrub, refer to the installgrub ( 1M ) man page.
Identify the slice that contains the existing root (/)
file system to be mirrored.
This example uses the slice c1t0d0s0.
Create a new RAID-0 volume on the slice from the previous step.
Only the single slice can be included in the RAID-0 volume. Use one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions. For more information, see the online help.
Use the following form of the metainit command:
# metainit -f volume-name number-of-stripes components-per-stripe component-name
f
Forces the command to continue. You must use this option when the slice contains a mounted file system.
volume-name
Specifies the name of the volume to create. For information on naming volumes, see Volume Names.
number-of-stripes
Specifies the number of stripes to create.
components-per-stripe
Specifies the number of components each stripe should have.
component-names
Specifies the names of the components that are used. This
example uses the root slice, c0t0d0s0.
Create a second RAID-0 volume (c1t1d0s0 in
this example) on an unused slice to act as the second submirror.
The secondary submirror must be the same size as the original submirror, or larger. Also, the slice you use as the second submirror must have a slice tag of “root” and the root slice must be slice 0.
For information on configuring the slice tag field, see the format ( 1M ) man page.
Use either of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action->Create Volume and follow the instructions on screen. For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name number-of-stripes components-per-stripes component-names
See Step 6 for an explanation of the options.
Create a one-way mirror by using one of the following methods:
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, then choose Action⇒Create Volume. Follow the onscreen instructions. For more information, see the online help.
Use the following form of the metainit command.
# metainit volume-name -m submirror-name
volume-name
Specifies the name of the volume to create.
m
Specifies to create a mirror.
submirror-name
Specifies the name of the component that will be the first submirror in the mirror. In this example, it is the RAID-0 volume that contains the root slice.
Remount your newly mirrored file system, then reboot the system.
#metaroot#volume-namereboot
For more information, see the metaroot ( 1M ) man page.
# metattach volume-name submirror-name
volume-name
Specifies the name of the RAID-1 volume on which to add the submirror.
submirror-name
Specifies the name of the component that will be the second submirror attached to the mirror.
See the metattach ( 1M ) man page for more information.
Define the alternative boot path in the menu.lst file.
To enable the system to boot off of the disk that holds the secondary
submirror, configure the system to see the disk as the alternate boot device.
In the current example, c1t1d0s0, the alternative path
is on the first slice of the first fdisk partition on the second disk. Thus,
you would edit the menu.lst with the following entry:
title alternate boot root (hd1,0,a) kernel /boot/multiboot module /boot/x86.miniroot-safe
To properly edit entries in menu.lst, you
must be familiar with disk-naming conventions in GRUB. For details, see Chapter 11, GRUB Based Booting (Tasks), in System Administration Guide: Basic Administration
After you have completed editing the menu.lst file,
the system is set to failover to the second disk. If the primary disk fails,
disk numbering changes so that the system boots from the secondary disk.
On certain cases, the automatic disk-renumbering feature of the BIOS might affect recovery from an unavailable primary disk. When disk renumbering forces the system to boot from the secondary disk, the primary disk's boot archive becomes stale. If the same primary disk becomes available later and you boot the system, the disk numbering switches again to use the default primary disk for the system boot. However, at this stage, the primary disk's boot archive remains stale. Consequently, the system might not boot at all. Therefore make sure that in such cases, you select the correct entry from the GRUB menu to boot the system from the valid boot archive. After the system completes the boot up process, perform the normal metadevice maintenance which synchronizes both primary and secondary disks and restores the valid boot archive to the primary disk.
After you mirror your root (/) file system, error
messages will be displayed in the console and logged in the system log that
is defined in the /etc/syslog.conf file. These error
messages do not indicate a problem. These messages are displayed for each
device type that you are not currently using, because an unused module cannot
be force loaded. The error messages are similar to the following:
Jul 13 10:17:42 ifr genunix: [ID 370176 kern.warning] WARNING: forceload of
misc/md_trans failed
Jul 13 10:17:42 ifr genunix: [ID 370176 kern.warning] WARNING: forceload of
misc/md_raid failed
Jul 13 10:17:42 ifr genunix: [ID 370176 kern.warning] WARNING: forceload of
misc/md_hotspares failed
You can safely disregard these error messages.