Using vxdiskadm


2.0 Volume Manager Configuration

Volume configuration consists of adding two or more disks to form disk group and create volume/s from this disk group. File system can be created on these volumes or these can be accessed as raw devices for some database applications. First step in volume manager configuration consists of adding and initializing disks under volume manager which creates a public region which is bulk of disk space available for volume space .Private region which is generally of a few megabytes stores the disk configuration information .

Most of the volume manager operation related to disks & volume can be performed by a character based menu utility call vxdiskadm

Following paragraphs describes the use of vxddiskadm to configure and manage volume manager.

 # vxdiskadm

Typing vxdiskadm brings up a menu based utility (text). The options , their explanation and screen shots are given below. Most of the options need a disk name , device name or disk group name and you can have this information by typing list in the vxdiskadm menu .The list menu option is used to display a list of disks attached to your system. This also lists removed or failed disks. Most useful to get a quick view of all disks or list details of a single disk - its name , volume association and status.

A disk needs to be formatted in order to be included in volume manager . volume manager will report unformatted disk as invalid and a will only recognize after formatting

By default all the available disks in the system are considered for inclusion as volume manager disk however to exclude certain disks, list the names of the disks to be excluded in the file /etc/vx/disks.exclude before the initialization or encapsulation. Similarly, you can exclude all disks on specific controllers from initialization or encapsulation by listing those controllers in the file /etc/vx/cntrls.exclude.

? & ?? options provide help about the menu item and menu system.

 # vxdiskadm

  Volume Manager Support Operations  
  Menu: VolumeManager/Disk  

  1    Add or initialize one or more disks  
  2    Encapsulate one or more disks  
  3    Remove a disk  
  4    Remove a disk for replacement  
  5    Replace a failed or removed disk  
  6    Mirror volumes on a disk  
  7    Move volumes from a disk  
  8    Enable access to (import) a disk group  
  9    Remove access to (deport) a disk group  
  10   Enable (online) a disk device  
  11   Disable (offline) a disk device  
  12   Mark a disk as a spare for a disk group  
  13   Turn off the spare flag on a disk  
  list List disk information  

  ?    Display help about menu  
  ??   Display help about the menuing system  
  q    Exit from menus  

  Select an operation to perform 


2.1 Add or initialize one or more disks

The formatted disks can be added or initialized with volume manager . Disk groups needs to be given for making a new group or adding disks in existing group. Default disk group is rootdg and if none is specified the disks are added to volume manager and are kept as hot spares which can be used in place of a failed disk.

Select 1 (Add or initialize one or more disks) from the vxdiskadm main menu. Add or initialize disks

 Menu: VolumeManager/Disk/AddDisks 
   Use this operation to add one or more disks to a disk group. You can 
   add the selected disks to an existing disk group or to a new disk group 
   that will be  created as a part of the operation. The selected disks may 
   also be added to a disk group as spares. The selected disks may also be 
   initialized without adding them to a disk group leaving the disks available
   for use as replacement disks.   

   More than one disk or pattern may be entered at the prompt. Here are some 
   disk selection examples:  

   all:           all disks  
   c3 c4t2:       all disks on both controller 3 and controller 4, target 2  
   c3t4d0:        a single disk  
   xyz_0 :       a single disk (in the enclosure based naming scheme)
   xyz_ :        all disks on the enclosure whose name is xyz


  Select disk devices to add: 
  [<pattern-list>,all,list,q,?]list 
  • <pattern-list> can be a single or more disks and/or controllers. If <pattern-list> consists of multiple items, those items must be separated by white space.
  • list at the prompt displays a list of the disks available to the system, followed by a prompt at which you should type the device name of the disk to be added:
  • All disks attached to the system are recognized by the Volume Manager and displayed here.. Error status indicates disks not recognized by volume manager as part of volume manager and can be used to add in the volume manager .. Disks with a name , group and online status are present in volume manager in a valid volume manager disk group .One or more disks separated by space can be selected for adding into volume manager.
  • You can choose to add this disk to an existing disk group, a new disk group, or leave the disk available for use by future add or replacement operations. To create a new disk group, select a disk group name that does not yet exist. To leave the disk available for future use, specify a disk group name of "none".
  Select disk devices to add: 
  [<pattern-list>,all,list,q,?]list 

  DEVICE       DISK         GROUP        STATUS  
  c0t0d0       disk01       rootdg       online  
  c0t1d0       disk02       rootdg       online  
  c0t2d0       disk03       rootdg       online  
  c0t3d0       -            -            online  
  c1t0d0       disk10       rootdg       online  
  c1t0d1       -            -            error  
  .  
  .  
  .  
  c3t0d0       -            -            error  
  c3t1d0       disk33       rootdg       online  
  c3t2d0       disk34       rootdg       online  
  c3t3d0       disk35       rootdg       online  

  Select disk devices to add: [<pattern-list>,all,list,q,?] c1t0d0  

   Here is the disk selected.  Output format: [Device_Name]  
    c1t0d0  

Continue operation? [y,n,q,?] (default: y) y
  You can choose to add this disk to an existing disk group, a
  new disk group, or leave the disk available for use by future
  add or replacement operations.  To create a new disk group,
  select a disk group name that does not yet exist.  To leave
  the disk available for future use, specify a disk group name
  of "none".

  Which disk group [<group>,none,list,q,?] (default: rootdg)   

  Use a default disk name for the disk? [y,n,q,?] (default: y)

  Add disk as a spare disk for rootdg? [y,n,q,?] (default: n) n  

  The selected disks will be added to the disk group rootdg with  
  default disk names.  

    c1t2d0  

  Continue with operation? [y,n,q,?] (default: y) y   

    The following disk device has a valid VTOC, but does not appear to have  
    been initialized for the Volume Manager.  If there is data on the disk  
    that should NOT be destroyed you should encapsulate the existing disk  
    partitions as volumes instead of adding the disk as a new disk.  
    Output format: [Device_Name]  

    c1t2d0  

  Encapsulate this device? [y,n,q,?] (default: y) n  

    c1t2d0  

  Instead of encapsulating, initialize? [y,n,q,?] (default: n) y   
  Initializing device c1t2d0.  
  Adding disk device c1t2d0 to disk group rootdg with disk  
  name disk39. 

  Add or initialize other disks? [y,n,q,?] (default: n)   


2.2 Encapsulate one or more disks

This is used to bring the disk under volume manager , which are already present in the system with data but without volume manager . Data on these disks are not disturbed and if these disks meets certain volume manager requirements these are added under volume manager.

  • System needs rebooting if encapsulation is used for disk with mounted filesystem or running applications . Also the old device names needs to be changed in applications/scripts to reflect the new volume name.
  • vfstab information is updated automatically but it is worthwhile to check vfstab if changes are proper as any discrepancy in vfstab may cause system boot failure on next reboot.
  • Encapsulation preserves any existing data on the disk when the disk is placed under volume manager control. To reduce the chance of encapsulation failure, make sure that the disk meets the following requirements:-
    • It has a small amount of free space (at the beginning or end of the disk) that does not belong to any partition
    • It has two free partitions
    • It has an s2 slice that represents the whole disk

Procedure for encapsulating a disk for volume manager use is as follows:

Select menu item 2 (Encapsulate one or more disks) from the vxdiskadm main menu and follow the prompts :-

 Encapsulate one or more disks  
 Menu: VolumeManager/Disk/Encapsulate  

 Use this operation to convert one or more disks to use the Volume Manager.
 This adds  the disks to a disk group and replaces existing partitions with 
 volumes.  Disk  encapsulation requires a reboot for the changes to take effect.  

 More than one disk or pattern may be entered at the prompt. Here are some 
 disk selection examples:  

    all:           all disks  
    c3 c4t2:       all disks on both controller 3 and controller 4, target 2  
    c3t4d0:        a single disk  

  Select disk devices to encapsulate:  
  [<pattern-list>,all,list,q,?] c2t5d0  

<pattern-list> can be a single disk, or a series of disks and/or controllers (with optional targets). If <pattern-list> consists of multiple items, those items must be separated by white space.

 Here is the disk selected.  Output format: [Device_Name]  
    c2t5d0  
  Continue operation? [y,n,q,?] (default: y) y   

    You can choose to add this disk to an existing disk group or to  
    a new disk group.  To create a new disk group, select a disk group
    name that does not yet exist.  

  Which disk group [<group>,list,q,?] (default: rootdg)  

 Use a default disk name for the disk? [y,n,q,?] (default: y) 
    The selected disks will be encapsulated and added to the rootdg  
    disk group with default disk names.  

    c2t5d0  

  Continue with operation? [y,n,q,?] (default: y) y 
  The following disk has been selected for encapsulation.  Output format:  
  [Device_Name]  

    c2t5d0  

  Continue with encapsulation? [y,n,q,?] (default: y) y   

    The disk device c2t5d0 will be encapsulated and added to the disk  
    group  rootdg with the disk name disk01.  
    The c2t5d0 disk has been configured for encapsulation.  
    The first stage of encapsulation has completed successfully.  You  
    should now reboot your system at the earliest possible opportunity.  
    The encapsulation will require two or three reboots which will happen 
    automatically after the next reboot.  To reboot execute the command:  
    shutdown -g0 -y -i6  
    This will update the /etc/vfstab file so that volume devices are  
    used to mount the file systems on this disk device.  You will need  
    to update any other references such as backup scripts, databases,
    or manually created swap devices.   

  Encapsulate other disks? [y,n,q,?] (default: n) n   

    The disk device c2t5d0 will be encapsulated and added to the 
    disk group rootdg with the disk name disk01.  
    The encapsulation operation failed with the following error:  
    It is not possible to encapsulate c2t5d0, for the following reason:  
    <vxvm:vxslicer: ERROR: Unsupported disk layout.>  

 Hit RETURN to continue. 
  • Encapsulation may fail if there is not enough free space available on the disk to accommodate volume manager. If this happens, the procedure above will end abruptly with an error message as above .


2.3 Remove a disk

This option is used to remove a disk from a disk group provided there is no active volume using this disk. If there are some volumes using the disk the those have to be either moved to some other disk or removed if they are no longer needed.

However since a diskgroup must have at least one disk you can not remove all the disks from a disk group . To remove all disks from a diskgroup you have to disable the volume group with the exception of rootdg disk group which can not be disabled .

Select menu item 3 (Remove a disk) from the vxdiskadm main menu.

  Remove a disk  
  Menu: VolumeManager/Disk/RemoveDisk  

  Use this operation to remove a disk from a disk group. This  
  operation takes, as input, a disk name. This is the same name  
  that you gave to the disk when you added the disk to the disk  
  group.  

  Enter disk name [<disk>,list,q,?] disk01 

  Requested operation is to remove disk disk01 from group rootdg.  

  Continue with operation? [y,n,q,?] (default: y)   

  Removal of disk disk01 is complete.  

  Remove another disk? [y,n,q,?] (default: n)


2.4 Remove a disk for replacement

This option is used for removing the disk but retaining the name of the disk so that it can be used by the newly replaced disk . The replacement disk can be a newly added disk or already available disk in the other disk groups

Select menu item 4 (Remove a disk for replacement) from the vxdiskadm main menu.

  Remove a disk for replacement  
  Menu: VolumeManager/Disk/RemoveForReplace  

  Use this menu operation to remove a physical disk from a disk  
  group, while retaining the disk name. This changes the state  
  for the disk name to a removed disk. If there are any  
  initialized disks that are not part of a disk group, you will be  
  given the option of using one of these disks as a replacement.  

  Enter disk name [<disk>,list,q,?] disk02  

Additional screens display if there are volumes associated with the disk you want to remove. You have to decide if data is needed or not needed and answer the prompts as asked .

 The following devices are available as replacements:  
       c1t1d0  

  You can choose one of these disks now, to replace disk02.  
  Select "none" if you do not wish to select a replacement disk.  

  Choose a device, or select "none"  
  [<device>,none,q,?] (default: c1t1d0)   

  Requested operation is to remove disk disk02 from group rootdg.  
  The removed disk will be replaced with disk device c1t1d0.  

  Continue with operation? [y,n,q,?] (default: y)

  Removal of disk disk02 completed successfully.  

  Proceeding to replace disk02 with device c1t1d0. 

    Disk replacement completed successfully. 

     Remove another disk? [y,n,q,?] (default: n) 


2.5 Replace a failed or removed disk

This option is used to replace a failed or removed disk . The new disk can be initialized or non initialized as this option does initialization .

Select menu item 5 (Replace a failed or removed disk) from the vxdiskadm main menu.

  Replace a failed or removed disk  
  Menu: VolumeManager/Disk/ReplaceDisk  

  Use this menu operation to specify a replacement disk for a disk  
  that you removed with the "Remove a disk for replacement" menu  
  operation, or that failed during use. You will be prompted for  
  a disk name to replace and a disk device to use as a replacement.  
  You can choose an uninitialized disk, in which case the disk will  
  be initialized, or you can choose a disk that you have already  
  initialized using the Add or initialize a disk menu operation.  

  Select a removed or failed disk [<disk>,list,q,?] disk02    

  The following devices are available as replacements:  
       c1t0d0s2 c1t1d0s2  

  You can choose one of these disks to replace disk02.  
  Choose "none" to initialize another disk to replace disk02.  

  Choose a device, or select "none"  
  [<device>,none,q,?] (default: c1t0d0s2)   

  The requested operation is to use the initialized device c1t0d0s2  
  to replace the removed or failed disk disk02 in disk group rootdg.  

  Continue with operation? [y,n,q,?] (default: y)  

  Replacement of disk disk02 in group rootdg with disk device  
  c1t0d0s2 completed successfully. 


2.6 Mirror volumes on a disk

volumes can be mirrored to another disk with available space however it can not be used to mirror existing mirrors or mirrors spanning more than one sub disk .

To mirror volumes on a disk, make sure that the target disk has an equal or greater amount of space as the originating disk and then do the following

Select menu item 6 (Mirror volumes on a disk) from the vxdiskadm main menu.

  Mirror volumes on a disk  
  Menu: VolumeManager/Disk/Mirror  

  This operation can be used to mirror volumes on a disk. These  
  volumes can be mirrored onto another disk or onto any  
  available disk space. Volumes will not be mirrored if they are  
  already mirrored. Also, volumes that are comprised of more than  
  one subdisk will not be mirrored.  

  Mirroring volumes from the boot disk will produce a disk that can  
  be used as an alternate boot disk.  

  Enter disk name [<disk>,list,q,?] disk02 

 You can choose to mirror volumes from disk disk02 onto any  
  available disk space, or you can choose to mirror onto a specific  
  disk. To mirror to a specific disk, select the name of that disk.  
  To mirror to any available disk space, select "any".  

  Enter destination disk [<disk>,list,q,?] (default: any) disk01    
  • Be sure to always specify the destination disk when you are creating an alternate root disk. Otherwise, the volume manager will select space available in the disk group which might span disk and will result in boot failure from this disk.


2.7 Move volumes from a disk

This option is used in case the disk is to be replaced or removed and has active volumes on the disk. . Also volumes can be moved to different disk groups for better space , performance etc.

Select menu item 7 (Move volumes from a disk) from the from the from the from the vxdiskadm main menu.

  Move volumes from a disk  
  Menu: VolumeManager/Disk/Evacuate  

  Use this menu operation to move any volumes that are using a  
  disk onto other disks. Use this menu immediately prior to  
  removing a disk, either permanently or for replacement. You can  
  specify a list of disks to move volumes onto, or you can move the  
  volumes to any available disk space in the same disk group.  

  NOTE: Simply moving volumes off of a disk, without also removing  
        the disk, does not prevent volumes from being moved onto  
        the disk by future operations. For example, using two  
        consecutive move operations may move volumes from the  
        second disk to the first.  

  Enter disk name [<disk>,list,q,?] disk01   


  You can now specify a list of disks to move onto.  Specify a list  
  of disk media names (e.g., disk01) all on one line separated by  
  blanks.  If you do not enter any disk media names, then the  
  volumes will be moved to any available space in the disk group.

 Requested operation is to move all volumes from disk disk01 in  
  group rootdg.  

  NOTE: This operation can take a long time to complete.  

  Continue with operation? [y,n,q,?] (default: y)  

  Move volume vol3 ...  
  Move volume vol3-bk00 ...  
  Evacuation of disk disk01 is complete. 

 Move volumes from another disk? [y,n,q,?] (default: n)   


2.8 Enable access to (import) a disk group

Used in enabling ownership of the other system to a disk group which has been deported by the other system. Used in failover configurations where the ownership of a shared disk/disk group is transferred to the other system in case of failure of current system.

Select menu item 8(Enable access to (import) a disk group) from the vxdiskadm main menu.

  Enable access to (import) a disk group  
  Menu: VolumeManager/Disk/EnableDiskGroup  

  Use this operation to enable access to a disk group. This can be  
  used as the final part of moving a disk group from one system to  
  another. The first part of moving a disk group is to use the  
  "Remove access to (deport) a disk group" operation on the  
  original host.  

  A disk group can be imported from another host that failed without  
  first deporting the disk group. Be sure that all disks in the disk  
  group are moved between hosts.  

  If two hosts share a SCSI bus, be very careful to ensure that the  
  other host really has failed or has deported the disk group. If  
  two active hosts import a disk group at the same time, the disk  
  group will be corrupted and will become unusable.  

  Select disk group to import [<group>,list,q,?] (default: list)  

  newdg   

 The import of newdg was successful.

Select another disk group? [y,n,q,?] (default: n)


2.9 Disable access to (deport) a disk group

Disk group is deported if disks groups ownership needs to be transferred to another system or all the disks in a disk groups needs to be freed from group. Disks in a disk groups to be deported should not be active.

Select menu item 9 (Remove access to (deport) a disk group) from the vxdiskadm main menu. Remove access to (deport) a disk group

  Menu: VolumeManager/Disk/DeportDiskGroup  

  Use this menu operation to remove access to a disk group that is  
  currently enabled (imported) by this system. Deport a disk  
  group if you intend to move the disks in a disk group to another  
  system. Also, deport a disk group if you want to use all of the  
  disks remaining in a disk group for some new purpose.  

  You will be prompted for the name of a disk group. You will also  
  be asked if the disks should be disabled (offlined). For  
  removable disk devices on some systems, it is important to  
  disable all access to the disk before removing the disk.  

  Enter name of disk group [<group>,list,q,?] (default: list) newdg   

  The requested operation is to disable access to the removable  
  disk group named newdg. This disk group is stored on the  
  following disks:  

      newdg01 on device c1t1d0s2  

  You can choose to disable access to (also known as "offline")  
  these disks. This may be necessary to prevent errors if  
  you actually remove any of the disks from the system.  

  Disable (offline) the indicated disks? [y,n,q,?] (default: n)  

  Continue with operation? [y,n,q,?] (default: y)  

  Removal of disk group newdg was successful. 

  Disable another disk group? [y,n,q,?] (default: n)


2.10 Enable (online) a disk device

Disks which are turned offline by volume manager , or which are to be imported can be enabled by this option. This operation causes disks to be scanned and find out the disk belonging to a disk group.

Select menu item 10 (Enable (online) a disk device) from the vxdiskadm main menu.

  Enable (online) a disk device  
  Menu: VolumeManager/Disk/OnlineDisk  

  Use this operation to enable access to a disk that was disabled  
  with the "Disable (offline) a disk device" operation.  

  You can also use this operation to re-scan a disk that may have  
  been changed outside of the Volume Manager. For example, if a disk  
  is shared between two systems, the Volume Manager running on the  
  other system may have changed the disk. If so, you can use this  
  operation to re-scan the disk.  

  NOTE: Many vxdiskadm operations re-scan disks without user  
        intervention. This will eliminate most needs to online a  
        disk directly, except when the disk is directly offlined.  

  Select a disk device to enable [<address>,list,q,?] c1t1d0    

  Enable another device? [y,n,q,?] (default: n)


2.11 Disable (offline) a disk device

This option disables all access to a disk which is not part of any disk group . This is used to remove disk from volume group. Some systems do not support disks that can be removed from a system during normal operation. On such systems, the offline operation is not very useful.

Select menu item 11 (Disable (offline) a disk device) from the vxdiskadm main menu.

  Disable (offline) a disk device  
  Menu: VolumeManager/Disk/OfflineDisk  

  Use this menu operation to disable all access to a disk device  
  by the Volume Manager. This operation can be applied only to  
  disks that are not currently in a disk group. Use this operation  
  if you intend to remove a disk from a system without rebooting.  

  NOTE: Many systems do not support disks that can be removed from  
        a system during normal operation. On such systems, the  
        offline operation is seldom useful.  

  Select a disk device to disable [<address>,list,q,?] c1t1d0    

  Disable another device? [y,n,q,?] (default: n)  


2.12 Mark a disk as a spare for a disk group

 This   is used to reserve the disk as an automatic replacement disk ( hot-relocation) in case of  another disk in the disk group  fails. Hot-relocation  relocates redundant subdisks to other disks and restores  the affected volume manager objects and data. If a disk has already been designated as a spare in the disk group, the subdisks from the failed disk are relocated to the spare disk. Otherwise, any suitable free space in the disk group is used.  

Select menu item 12 (Mark a disk as a spare for a disk group) from the vxdiskadm main menu.

  Mark a disk as a spare for a disk group  
  Menu: VolumeManager/Disk/MarkSpareDisk  

    Use this operation to mark a disk as a spare for a disk group.  
    This operation takes, as input, a disk name. This is the same name  
    that you gave to the disk when you added the disk to the disk group.  

  Enter disk name [<disk>,list,q,?] disk01   
  Marking of disk01 in rootdg as a spare disk is complete.  


  Mark another disk as a spare? [y,n,q,?] (default: n)  
  • Any VM disk in this disk group can now use this disk as a spare in the event of a failure. If a disk fails, hot-relocation should automatically occur .The failed disk needs to be replaced.


2.13 Turn off the spare flag on a disk

This is used to remove a VM Disk From the Hot-Relocation Pool & free hot-relocation spare disks for use as regular volume manager disks While a disk is designated as a spare, the space on that disk is not used as free space for the creation of volume manager objects within its disk group and this option makes this space available.

Select menu item 13 (Turn off the spare flag on a disk) from the vxdiskadm main menu.

  Turn off the spare flag on a disk  
  Menu: VolumeManager/Disk/UnmarkSpareDisk  

    Use this operation to turn off the spare flag on a disk.  
    This operation takes, as input, a disk name. This is the same  
    name that you gave to the disk when you added the disk to the  
    disk group.  

  Enter disk name [<disk>,list,q,?] disk01   

  Disk disk01 in rootdg no longer marked as a spare disk.

  Turn-off spare flag on another disk? [y,n,q,?] (default: n)