Vxvm Creating Volume and File System

7/23/2019 Vxvm Creating Volume and File System

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Lessons Learnt Creating Volume

and file system -

VXVM

Prepared By

F. Mohaideen Abdul Kader

Document Type: Lessons LearntWIPRO LIMITED


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Creating Volume and file system

VxVM allows a system administrator to configure various volume layouts for the volume thus

allowing high redundancy and high performance. Let us see how we can create a basic volume and a

file system with Veritas Volume Manager.

I have added six, 1 GB disks (other than two, 16 GB disks for root mirroring) to my vmware virtual

machine for future tutorials.

To check all the disks scanned under the Operating System:

# vxdiskeo alldgs list

DEVICE TYPE DISK GROUP STATUS OS_NATIVE_NAME ATTR

disk_8 auto:none - - online invalid c1t0d0s2 -








OS native Vs Enclosure based naming Scheme

We can have disks naming scheme in 2 waysOS native and Enclosure based. For my convenience I

will be using OS native disk scheming. But you can have it your way. To change the scheme usevxdiskadm command and select option 20. You can use enclosure based naming scheme if you

prefer that. You would see the difference in the DEVICE column in the output of vxdisk -eoalldgs

list as shown above and below in the vxdisk command output.

To check the current naming scheme

# vxddladm get namingscheme

NAMING_SCHEME PERSISTENCE LOWERCASE USE_AVID

============================================================

OS Native No Yes Yes

To change the naming scheme through command line

# vxddladm set namingscheme=ebn

# vxddladm get namingscheme

NAMING_SCHEME PERSISTENCE LOWERCASE USE_AVID

============================================================

Enclosure Based Yes Yes Yes


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# vxdiskeo alldgs list


c1t0d0s2 auto:none - - online invalid c1t0d0s2 -








I would exclude the root disk (c1t0d0) and a disk supposed to be mirrored (c1t1d0) with it later on.

# df -h /

Filesystem size used avail capacity Mounted on

/dev/dsk/c1t0d0s0 15G 5.9G 8.6G 41% /

Now first initialize the disk we want to use for the disk group creation. If you have seen output of

vxdisk list, you would see all the disks with STATUS of online invalid. This indicates that the disk is

not under VxVM control. To take it under VxVM control we would initialize it.

# vxdisksetup -i c1t2d0

vxdiks list would now show you the status as online implying that the disk is now under VxVM

control.

# vxdisk list

DEVICE TYPE DISK GROUP STATUS

c1t0d0s2 auto:none - - online invalid


c1t2d0s2 auto:cdsdisk - - online






Initialization Vs Encapsulation

Now before going forward let us see whats the difference between encapsulation and initialization.

Initialization When a disk is initialized a private and public region is created on the disk (placed

under VxVM control) and VM disk header information is written to the private region. All the data

already present on the disk is erased.

Encapsulation Disk is taken under VxVM control when it is initialized but the data is preserved in

this method.


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Now create the disk group mydg by specifying the disk we just initialized. You can give any name to

disk you prefer instead of disk01.

# vxdg init mydg disk01=c1t2d0

bash-3.2# vxdg list

NAME STATE ID

mydg enabled,cds 1381663220.16.geeklab

bash-3.2# vxdiskeo alldgs list




c1t2d0s2 auto:cdsdisk disk01 mydg online c1t2d0s2 -


c1t4d0s2 auto:none - - online invalid c1t4d0s2 -c1t5d0s2 auto:none - - online invalid c1t5d0s2 -



Now create a simple concatenated volume myvol of around 500 MB size in the mydg.

# vxassist -g mydg make myvol 500m

Create a vxfs file system on this volume and also create a directory to mount this volume.

# mkfs -F vxfs /dev/vx/rdsk/mydg/myvol

To make the mount to persists after reboot you can add an entry to /etc/vfstab. Also it is a preferred

way to check the entry in vfstab by mounting it with just mount /mount -point or mountall

command.

# cat /etc/vfstab |grep data

/dev/vx/dsk/mydg/myvol /dev/vx/rdsk/mydg/myvol /data vxfs 0 yes -

# mount /data ( or mountall)

bash-3.2# df -h |grep data

/dev/vx/dsk/mydg/myvol 500M 2.2M 467M 1% /data

Adding a new disk to the existing disk group

We can also add disks after we create the disk group. Before adding a new disk initialize it.

# vxdisksetup -i c1t3d0

# vxdg -g mydg adddisk disk02=c1t3d0


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To check the layout of the volume we just create:

# vxprint -g mydg -htr

.............

dg mydg default default 28000 1381663220.16.geeklab

dm disk01 c1t2d0s2 auto 65536 2027168 -

dm disk02 c1t3d0s2 auto 65536 2027168 -

v myvol - ENABLED ACTIVE 1024000 SELECT - fsgen

pl myvol-01 myvol ENABLED ACTIVE 1024000 CONCAT - RW

sd disk01-01 myvol-01 disk01 0 1024000 0 c1t2d0 ENA

As you can see in the output above, a plex with one subdisk is created which comprises the volume

myvol. You can also see the layout as concat in the 6th column.

To check the disk property of a disk in the mydg :

# vxdisk -p list c1t2d0

DISK : c1t2d0s2

DISKID : 1381663112.11.geeklab

VID : VMware,

UDID :

VMware%2C%5FVMware%20Virtual%20S%5FDISKS%5F6000C2952A4E5B4ACE2B2AE07A473A35

SCSI_VERSION : 2

REVISION : 1.0PID : VMware Virtual S

PHYS_CTLR_NAME : /pci@0,0/pci15ad,1976@10

MEDIA_TYPE : hdd

LUN_SNO_ORDER : 0

LUN_SERIAL_NO : 6000C2952A4E5B4ACE2B2AE07A473A35

LIBNAME : scsi3_jbod

DMP_DEVICE : c1t2d0

CAB_SERIAL_NO : DISKS

ATYPE : Disk

ARRAY_PORT_PWWN:

ANAME : Disk

TRANSPORT : SCSI

Remove volume , diks and diskgroups

Before removing the volume umount the mount point /data and remove the entry from vfstab.

# umount /data

After removing the volume you can remove the disks in the diskgroup. But the last disk can not be

removed. For that we have to remove the entire disk group mydg. After removing the DG we can use

these disks in any other DG.


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# vxassist -g mydg remove volume myvol

# vxdg -g mydg rmdisk disk02

# vxdg -g mydg rmdisk disk01

VxVM vxdg ERROR V-5-1-10127 disassociating disk-media disk01:

Cannot remove last disk in disk group

# vxdg destroy mydg

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Vxvm Creating Volume and File System