Posts Tagged ‘group’

Useful Commands for Redhat LVM and increasing Filesystem

– Scan New Hardware:
scsi-rescan
rescan-scsi-bus.sh –forcerescan

– For Physical Volumes:
pvdisplay
pvscan
pvcreate /dev/sdb

– For Volume Groups:
vgdisplay
vgscan
vgextend VGNAME PVNAME
lvextend -L+50G LVNAME
resize2fs LVNAME

Volume Group Status Area (VGSA)

Information about which PPs that are stale and which PVs are missing within a VG. The LVM and SCSI driver reserves somewhere between 7-10% of the available disk space for LVM maps, etc.

Ref:

http://www.datadisk.co.uk/html_docs/hp/aix_lvm.htm

Volume Group Descriptor Area (VGDA)

Information about all the LVs and PVs within a VG. The first 64K of a PV is reserved for this area – defined in <sys/bootrecord.h>.

The VGDA consists of

  • BOOTRECORD: – first 512 bytes. Allows the Read Only System (ROS) to boot system
  • BAD BLK DIRECTORY – found in <sys/bddir.h>
  • LVM RECORD – found in <lvmrec.h>

Volume Group Characteristics

You can find below the meaning of each parameter on Volume Group Characteristics (the output from lsvg vg command):

 

  1. Volume Group: Name of Volume Group.
  2. VG State: active/partial. Partial indicates that some of the Physical Volumes in the Volume Group are not active.
  3. VG Permission: It indicates if the volume group is read-only or read-write.
  4. Max LVs: Maximum number of Logical Volumes allowed in Volume Group.
  5. LVs: Total number of Logical Volumes at present in Volume Group.
  6. Open LVs: Number of LVs open at present in the Volume Group for any Read Write operation.
  7. Total PVs: Total number of Physical Volumes present in Volume Group.
  8. Stale PVs: How many stale Physical Volumes are there in Volume Group. The stale Physical Volumes are those ones on which I/O operations are not possible.
  9. Active PVs: Total number of Physical Volumes which are active in Volume Group.
  10. Max PPs per VG: Maximum no. of Physical Partitions which can be there in the Volume Group.
  11. Max PPs per PV: Maximum number of Physical Partitions which can be there in Physical Volume.
  12. VG Identifier: The very long string to identify Volume Group.
  13. PP Size: The size of Physical Partition used in every Physical Volume of Volume Group.
  14. Total PPs: Total number of Physical Partitions in Volume Group.
  15. Free PPs: Total number of free Physical Partitions with in Volume Group.
  16. Used PPs: Total number of Physical Partitions in use in Volume Group.
  17. Quorum: Whether the quorum is on or not in Volume Group.
  18. VG Descriptors: Number of Volume Group Descriptor Areas(VGDA) in Volume Group.
  19. Stale PPs: How many Physical Partitions are stale or unable to perform I/O operations.
  20. Auto On: Whether the Volume Group will varyon on system startup or not.
  21. Max PVs: Maximum number of Physical Volumes allowed in this Volume Group.
  22. Auto Sync: Whether this Volume Group should sync automatically or not.
  23. BB Policy: Its bad block relocation policy. So, this value here is relocatable, that means we are allowed to relocate bad blocks in this Volume Group if need be.

how to know the Major Number for Specific Volume Group

to list the Major number for Specific Volume Group, use the following Command :
“lvgenmajor VOLUME_GROUP_NAME”

for example :

# lvgenmajor rootvg
10

and the following link show how to display the available Major Numbers:

how to list file system inside specific volume group

You can use command ‘lsvgfs’ to list all file systems inside specific volume group like the following example:

# lsvgfs rootvg
/
/usr
/var
/tmp
/home
/opt
/admin
/var/adm/ras/livedump
/oracle_osb
/u01/app/oracle
/u02/oradata
/iso_image
/TestFs

how to know the volume group of specified logical volume

if you need to know the volume group of specified logical volume(AIX System with HACMP), you can run the following command :

#/usr/es/sbin/cluster/utilities/clgetvg -l hd5
rootvg

0516-082 varyonvg: Unable to access a special device file

if you got the following errot while you trying to vary on a volume group:

#varyonvg testvg
0516-082 varyonvg: Unable to access a special device file.
         Execute redefinevg and synclvodm to build correct environment.