Veritas Volume Manager – vxassist

Veritas Volume Manager – 2 covers vxassist command for volume
management .
vxassist utility in Veritas Volume Manager is used to create volumes, add mirrors and logs to existing volumes, extend and shrink existing volumes, provides for the migration of data from a specified set of disks, and provides facilities for the on-line backup of existing volumes.
The default behavior of vxassist is to create volumes in the rootdg diskgroup if diskgroup is not specified . The default length is taken as number of blocks but this can be specified in Kilobytes or Megabytes or Gigabytes.

About Vxassist
1. Creating a Volume
    1.1 Creating a Concatenated Volume
    1.2 Creating a Striped Volume
    1.3 Creating a RAID-5 Volume
2. Extending a Volume
    2.1 Extending a volume up to certain length,
    2.2 Extending by a Given Length
3. Shrinking a Volume
    3.1 Shrinking to a Given Length
    3.2 Shrinking by a Given Length
4. Removing a Volume
5. Mirroring a Volume
    5.1 Creating & Mirroring a New Volume
    5.2 Mirroring an Existing Volume
    5.3 Mirroring All Volumes
6. Removing a Mirror
7. Adding a RAID-5 Log
8. Adding a DRL Log
9.  Removing a RAID-5 Log
10.Preparing a Volume for Online Backup
11.Displaying Volume Configuration Information
12.Next Steps

About vxassist
vxassist command syntax :
vxassist volume_name [attributes]
Commonly used options are given below (See man vxassist for complete list of supported options)
-g for specifying diskgroups
-b for background operation
-d file containing defaults for vxassist if not specified /etc/default/vxassist is used
Keywords used are make , mirror , move , growto ,growby ,shrintto ,shirnkby ,snapstart , snapshot ,snapwait
Attributes specify volumes layout disks controllar to include exclude etc
Device Nodes
Default rootdg disk group.
Block Device Node /dev/vx/dsk/volume_name
Raw Device Node /dev/vx/rdsk/volume_name
Other DiskGroups
Block Device Node /dev/vx/dsk/diskgroup_name/volume_name
Raw Device Node /dev/vx/rdsk/diskgroup_name/volume_name

1. Creating a Volume
1.1 Creating a Concatenated Volume
By default, vxassist creates a concatenated volume using the space available on a disk or on the number of disks in a diskgroup if the volume size specified is more then the one available on a single disk.
Disks can be specified from a diskgroup for a volume group but if not mentioned available disks are selected by the volume manager.
Command syntax :
· #vxassist make volume_name volume_length
To create a new volume appvol of 100 MB in the default disk group rootdg with available disks:
· #vxassist make appvol 100m
To create the volume appvol of 100MB on disk03
· #vxassist make appvol 100m disk03
1.2 Creating a Striped Volume
A striped volume contains at least one plex that consists of two or more subdisks located on two or more physical disks.
Command Syntax
· vxassist make volume_name length layout=stripe
To create a striped volume appvol2 with the default stripe unit size on the default number of disks
· #vxassist make appvol2 100m layout=stripe
To create a striped volume appvol2 100MB striped volume on three specific disks.
· #vxassist make appvol2 100m layout=stripe disk04 disk05 disk06
1.3 Creating a RAID-5 Volume
A RAID-5 volume contains a RAID-5 plex that consists of two or more subdisks located on two or more physical disks. Only one RAID-5 plex can exist per volume. A RAID-5 volume may also contain one or more RAID-5 log plexes, which are used to log information about data and parity being written to the volume.
Command Syntax :
· vxassist make volume_name length layout=raid5
To create the RAID-5 volume appvol4 with the default stripe unit size on the default number of disks with RAID-5 log,
· #vxassist make appvol4 100m layout=raid5.