Veritas InfoScale™ 7.4.2 Troubleshooting Guide - Linux

To clean up the system configuration

1. After recovering the VxVM configuration, you must determine which volumes need to be restored from backup because a complete copy of their data is not present on the recovered disks. Such volumes are invalid and must be removed, recreated, and restored from backup. If a complete copy of a volume's data is available, it can be repaired by the hot-relocation feature provided that this is enabled and there is sufficient spare disk space in the disk group.

   Establish which VM disks have been removed or reinstalled using the following command:

   # vxdisk list

   This displays a list of system disk devices and the status of these devices. For example, for a reinstalled system with three disks and a reinstalled root disk, the output of the vxdisk list command is similar to this:

   DEVICE    TYPE      DISK      GROUP      STATUS
   sdb       simple    -         -          error
   sdc       simple    disk02    bootdg     online
   sdd       simple    disk03    bootdg     online
   -         -         disk01    bootdg     failed was:sdb

   The display shows that the reinstalled root device, sdb, is not associated with a VM disk and is marked with a status of error. The disks disk02 and disk03 were not involved in the reinstallation and are recognized by VxVM and associated with their devices (sdc and sdd). The former disk01, which was the VM disk associated with the replaced disk device, is no longer associated with the device (sdb).

   If other disks (with volumes or mirrors on them) had been removed or replaced during reinstallation, those disks would also have a disk device listed in error state and a VM disk listed as not associated with a device.

2. Once you know which disks have been removed or replaced, locate all the mirrors on failed disks using the following command:

   # vxprint -sF "%vname" -e 'sd_disk = "disk"'

   where disk is the name of a disk with a failed status. Be sure to enclose the disk name in quotes in the command. Otherwise, the command returns an error message. The vxprint command returns a list of volumes that have mirrors on the failed disk. Repeat this command for every disk with a failed status.

3. Check the status of each volume and print volume information using the following command:

   # vxprint -th volume 

   where volume is the name of the volume to be examined. The vxprint command displays the status of the volume, its plexes, and the portions of disks that make up those plexes. For example, a volume named v01 with only one plex resides on the reinstalled disk named disk01. The vxprint -th v01 command produces the following output:

   V    NAME      USETYPE   KSTATE     STATE     LENGTH    READPOL     PREFPLEX
   PL   NAME      VOLUME    KSTATE     STATE     LENGTH    LAYOUT      NCOL/WID   MODE
   SD   NAME      PLEX      DISK       DISKOFFS  LENGTH    [COL/]OFF   DEVICE     MODE
   
   v    v01       fsgen     DISABLED   ACTIVE    24000     SELECT      -
   pl   v01-01    v01       DISABLED   NODEVICE  24000     CONCAT      -          RW
   sd   disk01-06 v0101     disk01     245759    24000     0           sdg        ENA

   The only plex of the volume is shown in the line beginning with pl. The STATE field for the plex named v01-01 is NODEVICE. The plex has space on a disk that has been replaced, removed, or reinstalled. The plex is no longer valid and must be removed.

4. Because v01-01 was the only plex of the volume, the volume contents are irrecoverable except by restoring the volume from a backup. The volume must also be removed. If a backup copy of the volume exists, you can restore the volume later. Keep a record of the volume name and its length, as you will need it for the backup procedure.

   Remove irrecoverable volumes (such as v01) using the following command:

     # vxedit -r rm v01
   

5. It is possible that only part of a plex is located on the failed disk. If the volume has a striped plex associated with it, the volume is divided between several disks. For example, the volume named v02 has one striped plex striped across three disks, one of which is the reinstalled disk disk01. The vxprint -th v02 command produces the following output:

   V    NAME     USETYPE    KSTATE    STATE     LENGTH     READPOL     PREFPLEX
   PL   NAME     VOLUME     KSTATE    STATE     LENGTH     LAYOUT      NCOL/WID  MODE
   SD   NAME     PLEX       DISK      DISKOFFS  LENGTH     [COL/]OFF   DEVICE    MODE
   
   v    v02      fsgen     DISABLED   ACTIVE     30720     SELECT      v02-01
   pl   v02-01   v02       DISABLED   NODEVICE   30720     STRIPE      3/128     RW
   sd   disk02-02v02-01    disk01     424144     10240     0/0         sdi       ENA
   sd   disk01-05v02-01    disk01     620544     10240     1/0         sdj       DIS
   sd   disk03-01v02-01    disk03     620544     10240     2/0         sdk       ENA

   The display shows three disks, across which the plex v02-01 is striped (the lines starting with sd represent the stripes). One of the stripe areas is located on a failed disk. This disk is no longer valid, so the plex named v02-01 has a state of NODEVICE. Since this is the only plex of the volume, the volume is invalid and must be removed. If a copy of v02 exists on the backup media, it can be restored later. Keep a record of the volume name and length of any volume you intend to restore from backup.

   Remove invalid volumes (such as v02) using the following command:

   # vxedit -r rm v02

6. A volume that has one mirror on a failed disk may also have other mirrors on disks that are still valid. In this case, the volume does not need to be restored from backup, since all the data is still available, and recovery can usually be handled by the hot-relocation feature provided that this is enabled.

   If hot-relocation is disabled, you can recover the mirror manually. In this example, the vxprint -th command for a volume with one plex on a failed disk (disk01) and another plex on a valid disk (disk02) produces the following output:

   V    NAME       USETYPE   KSTATE    STATE     LENGTH   READPOL    PREFPLEX
   PL   NAME       VOLUME    KSTATE    STATE     LENGTH   LAYOUT     NCOL/WID   MODE
   SD   NAME       PLEX      DISK      DISKOFFS  LENGTH   [COL/]OFF  DEVICE     MODE
   
   v    v03        fsgen     DISABLED  ACTIVE    0720     SELECT      -
   pl   v03-01     v03       DISABLED  ACTIVE    30720    CONCAT      -         RW
   sd   disk02-01 v03-01     disk01    620544    30720    0           sdl       ENA
   pl   v03-02     v03       DISABLED  NODEVICE  30720    CONCAT      -         RW
   sd   disk01-04 v03-02     disk03    262144    30720    0           sdm       DIS

   This volume has two plexes, v03-01 and v03-02. The first plex (v03-01) does not use any space on the invalid disk, so it can still be used. The second plex (v03-02) uses space on invalid disk disk01 and has a state of NODEVICE. Plex v03-02 must be removed. However, the volume still has one valid plex containing valid data. If the volume needs to be mirrored, another plex can be added later. Note the name of the volume to create another plex later.

   To remove an invalid plex, use the vxplex command to dissociate and then remove the plex from the volume. For example, to dissociate and remove the plex v03-02, use the following command:

   # vxplex -o rm dis v03-02

7. Once all invalid volumes and plexes have been removed, the disk configuration can be cleaned up. Each disk that was removed, reinstalled, or replaced (as determined from the output of the vxdisk list command) must be removed from the configuration.

   To remove the disk, use the vxdg command. To remove the failed disk disk01, use the following command:

   # vxdg rmdisk disk01

   If the vxdg command returns an error message, invalid mirrors exist.

   Repeat step 1 through step 6 until all invalid volumes and mirrors are removed.

8. Once all the invalid disks have been removed, the replacement or reinstalled disks can be added to Veritas Volume Manager control. If the root disk was originally under Veritas Volume Manager control or you now wish to put the root disk under Veritas Volume Manager control, add this disk first.

   To add the root disk to Veritas Volume Manager control, use the vxdiskadm command:

   # vxdiskadm

   From the vxdiskadm main menu, select menu item 2 (Encapsulate a disk). Follow the instructions and encapsulate the root disk for the system.

9. When the encapsulation is complete, reboot the system to multi-user mode.
10. Once the root disk is encapsulated, any other disks that were replaced should be added using the vxdiskadm command. If the disks were reinstalled during the operating system reinstallation, they should be encapsulated; otherwise, they can be added.
11. Once all the disks have been added to the system, any volumes that were completely removed as part of the configuration cleanup can be recreated and their contents restored from backup. The volume recreation can be done by using the vxassist command or the graphical user interface.

    For example, to recreate the volumes v01 and v02, use the following commands:

    # vxassist make v01 24000 
    # vxassist make v02 30720 layout=stripe nstripe=3

    Once the volumes are created, they can be restored from backup using normal backup/restore procedures.

12. Recreate any plexes for volumes that had plexes removed as part of the volume cleanup. To replace the plex removed from volume v03, use the following command:

    # vxassist mirror v03

    Once you have restored the volumes and plexes lost during reinstallation, recovery is complete and your system is configured as it was prior to the failure.