Because Solaris Volume Manager enables you to mirror the root (/), swap, and /usr directories, special problems can arise when you boot the system. These problems can arise either through hardware failures or operator error. The procedures in this section provide solutions to such potential problems.
The following table describes these problems and points you to the appropriate solution.
Table 25-1 Common Boot Problems With Solaris Volume Manager
If Solaris Volume Manager takes a volume offline due to errors, unmount all file systems on the disk where the failure occurred.
Because each disk slice is independent, multiple file systems can be mounted on a single disk. If the software has encountered a failure, other slices on the same disk will likely experience failures soon. File systems that are mounted directly on disk slices do not have the protection of Solaris Volume Manager error handling. Leaving such file systems mounted can leave you vulnerable to crashing the system and losing data.
Minimize the amount of time you run with submirrors that are disabled or offline. During resynchronization and online backup intervals, the full protection of mirroring is gone.
If you have made an incorrect entry in the /etc/vfstab file, for example, when mirroring the root (/) file system, the system appears at first to be booting properly. Then, the system fails. To remedy this situation, you need to edit the /etc/vfstab file while in single-user mode.
The high-level steps to recover from improper /etc/vfstab file entries are as follows:
Booting the system to single-user mode
Running the fsck command on the mirror volume
Remounting file system read-write options enabled
Optional: running the metaroot command for a root (/) mirror
Verifying that the /etc/vfstab file correctly references the volume for the file system entry
Rebooting the system
In the following example, the root (/) file system is mirrored with a two-way mirror, d0. The root (/) entry in the /etc/vfstab file has somehow reverted back to the original slice of the file system. However, the information in the /etc/system file still shows booting to be from the mirror d0. The most likely reason is that the metaroot command was not used to maintain the /etc/system and /etc/vfstab files. Another possible reason is that an old copy of the/etc/vfstab file was copied back into the current /etc/vfstab file.
The incorrect /etc/vfstab file looks similar to the following:
#device device mount FS fsck mount mount #to mount to fsck point type pass at boot options # /dev/dsk/c0t3d0s0 /dev/rdsk/c0t3d0s0 / ufs 1 no - /dev/dsk/c0t3d0s1 - - swap - no - /dev/dsk/c0t3d0s6 /dev/rdsk/c0t3d0s6 /usr ufs 2 no - # /proc - /proc proc - no - swap - /tmp tmpfs - yes -
Because of the errors, you automatically go into single-user mode when the system is booted:
ok boot ... configuring network interfaces: hme0. Hostname: host1 mount: /dev/dsk/c0t3d0s0 is not this fstype. setmnt: Cannot open /etc/mnttab for writing INIT: Cannot create /var/adm/utmp or /var/adm/utmpx INIT: failed write of utmpx entry:" " INIT: failed write of utmpx entry:" " INIT: SINGLE USER MODE Type Ctrl-d to proceed with normal startup, (or give root password for system maintenance): <root-password>
At this point, the root (/) and /usr file systems are mounted read-only. Follow these steps:
Note - Be careful to use the correct volume for the root (/) mirror.
# fsck /dev/md/rdsk/d0 ** /dev/md/rdsk/d0 ** Currently Mounted on / ** Phase 1 - Check Blocks and Sizes ** Phase 2 - Check Pathnames ** Phase 3 - Check Connectivity ** Phase 4 - Check Reference Counts ** Phase 5 - Check Cyl groups 2274 files, 11815 used, 10302 free (158 frags, 1268 blocks, 0.7% fragmentation)
# mount -o rw,remount /dev/md/dsk/d0 / mount: warning: cannot lock temp file </etc/.mnt.lock>
# metaroot d0
This command edits the /etc/system and /etc/vfstab files to specify that the root (/) file system is now on volume d0.
The root (/) entry in the /etc/vfstab file should appear as follows so that the entry for the file system correctly references the RAID-1 volume:
#device device mount FS fsck mount mount #to mount to fsck point type pass at boot options # /dev/md/dsk/d0 /dev/md/rdsk/d0 / ufs 1 no - /dev/dsk/c0t3d0s1 - - swap - no - /dev/dsk/c0t3d0s6 /dev/rdsk/c0t3d0s6 /usr ufs 2 no - # /proc - /proc proc - no - swap - /tmp tmpfs - yes -
The system returns to normal operation.
If you have a root (/) mirror and your boot device fails, you need to set up an alternate boot device.
The high-level steps in this task are as follows:
Booting from the alternate root (/) submirror
Determining the erred state database replicas and volumes
Repairing the failed disk
Restoring state database replicas and volumes to their original state
Initially, when the boot device fails, you'll see a message similar to the following. This message might differ among various architectures.
Rebooting with command: Boot device: /iommu/sbus/dma@f,81000/esp@f,80000/sd@3,0 The selected SCSI device is not responding Can't open boot device ...
When you see this message, note the device. Then, follow these steps:
Since only two of the six state database replicas in this example are in error, you can still boot. If this were not the case, you would need to delete the inaccessible state database replicas in single-user mode. This procedure is described in How to Recover From Insufficient State Database Replicas.
When you created the mirror for the root (/) file system, you should have recorded the alternate boot device as part of that procedure. In this example, disk2 is that alternate boot device.
ok boot disk2 SunOS Release 5.9 Version s81_51 64-bit Copyright 1983-2001 Sun Microsystems, Inc. All rights reserved. Hostname: demo ... demo console login: root Password: <root-password> Dec 16 12:22:09 host1 login: ROOT LOGIN /dev/console Last login: Wed Dec 12 10:55:16 on console Sun Microsystems Inc. SunOS 5.9 s81_51 May 2002 ...
# metadb flags first blk block count M p unknown unknown /dev/dsk/c0t3d0s3 M p unknown unknown /dev/dsk/c0t3d0s3 a m p luo 16 1034 /dev/dsk/c0t2d0s3 a p luo 1050 1034 /dev/dsk/c0t2d0s3 a p luo 16 1034 /dev/dsk/c0t1d0s3 a p luo 1050 1034 /dev/dsk/c0t1d0s3
In this example, the system can no longer detect state database replicas on slice /dev/dsk/c0t3d0s3, which is part of the failed disk.
# metastat d0: Mirror Submirror 0: d10 State: Needs maintenance Submirror 1: d20 State: Okay ... d10: Submirror of d0 State: Needs maintenance Invoke: "metareplace d0 /dev/dsk/c0t3d0s0 <new device>" Size: 47628 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t3d0s0 0 No Maintenance d20: Submirror of d0 State: Okay Size: 47628 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t2d0s0 0 No Okay d1: Mirror Submirror 0: d11 State: Needs maintenance Submirror 1: d21 State: Okay ... d11: Submirror of d1 State: Needs maintenance Invoke: "metareplace d1 /dev/dsk/c0t3d0s1 <new device>" Size: 69660 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t3d0s1 0 No Maintenance d21: Submirror of d1 State: Okay Size: 69660 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t2d0s1 0 No Okay d2: Mirror Submirror 0: d12 State: Needs maintenance Submirror 1: d22 State: Okay ... d12: Submirror of d2 State: Needs maintenance Invoke: "metareplace d2 /dev/dsk/c0t3d0s6 <new device>" Size: 286740 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t3d0s6 0 No Maintenance d22: Submirror of d2 State: Okay Size: 286740 blocks Stripe 0: Device Start Block Dbase State Hot Spare /dev/dsk/c0t2d0s6 0 No Okay
In this example, the metastat command shows that the following submirrors need maintenance:
Submirror d10, device c0t3d0s0
Submirror d11, device c0t3d0s1
Submirror d12, device c0t3d0s6
Tip - If the new disk is identical to the existing disk (the intact side of the mirror, in this example), quickly format the new disk. To do so, use the prtvtoc /dev/rdsk/c0t2d0s2 | fmthard -s - /dev/rdsk/c0t3d0s2 command (c0t3d0, in this example).
# halt ... Halted ... ok boot ... # format /dev/rdsk/c0t3d0s0
Note that you must reboot from the other half of the root (/) mirror. You should have recorded the alternate boot device when you created the mirror.
# halt ... ok boot disk2
# metadb flags first blk block count M p unknown unknown /dev/dsk/c0t3d0s3 M p unknown unknown /dev/dsk/c0t3d0s3 a m p luo 16 1034 /dev/dsk/c0t2d0s3 a p luo 1050 1034 /dev/dsk/c0t2d0s3 a p luo 16 1034 /dev/dsk/c0t1d0s3 a p luo 1050 1034 /dev/dsk/c0t1d0s3 # metadb -d c0t3d0s3 # metadb -c 2 -a c0t3d0s3 # metadb flags first blk block count a m p luo 16 1034 /dev/dsk/c0t2d0s3 a p luo 1050 1034 /dev/dsk/c0t2d0s3 a p luo 16 1034 /dev/dsk/c0t1d0s3 a p luo 1050 1034 /dev/dsk/c0t1d0s3 a u 16 1034 /dev/dsk/c0t3d0s3 a u 1050 1034 /dev/dsk/c0t3d0s3
# metareplace -e d0 c0t3d0s0 Device /dev/dsk/c0t3d0s0 is enabled # metareplace -e d1 c0t3d0s1 Device /dev/dsk/c0t3d0s1 is enabled # metareplace -e d2 c0t3d0s6 Device /dev/dsk/c0t3d0s6 is enabled
After some time, the resynchronization will complete. You can now return to booting from the original device.