How to determine free space in a disk group using the vxassist maxsize and maxgrow commands
Article ID: 100000497
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Description
Description
The article describes how to determine the free space in a Veritas Volume Manager (VxVM) disk group using the vxassist maxsize and maxgrow commands.
There are several ways to determine both the contiguous and total free space that is available in a disk group. The output is in 512 byte sectors by default (except on HP-UX systems, which uses 1024 byte segments).
From the command line:
1. To determine regions of total free space on all disks across all imported disk groups:
From the command line:
1. To determine regions of total free space on all disks across all imported disk groups:
# vxdg free
2. To determine regions of total free space for a specific imported disk group, type:
2. To determine regions of total free space for a specific imported disk group, type:
# vxdg -g free
When querying the system to determine how much space will be available for a particular volume, it is crucial you specify the volume layout for the type of volume you are going to create, e.g.
Using the following disk group "tdg" (Each LUN is 2G in size):
When querying the system to determine how much space will be available for a particular volume, it is crucial you specify the volume layout for the type of volume you are going to create, e.g.
Using the following disk group "tdg" (Each LUN is 2G in size):
# vxdg -g tdg free
The vxassist "maxsize" argument helps determine the maximum volume size that can be created for specified diskgroup "tdg":
DEVICE TYPE DISK GROUP STATUS
sdb auto:sliced disk01 tdg online
sdc auto:sliced disk02 tdg online
sdd auto:sliced disk03 tdg onlineThe vxassist "maxsize" argument helps determine the maximum volume size that can be created for specified diskgroup "tdg":
# vxassist -g tdg maxsize
NOTE: The maxsize operation will use the default concatenated (concat) layout by default to establish the maximum volume size.
To indicate a different volume layout use the "layout" parameter:
Maximum volume size: 12472320(6090Mb) NOTE: The maxsize operation will use the default concatenated (concat) layout by default to establish the maximum volume size.
To indicate a different volume layout use the "layout" parameter:
# vxassist -g tdg maxsize layout=striped
The available size has changed for the above example from 6090Mb (concat layout) to 4060Mb for the striped volume layout. The default stripe column count is 2 columns, when no column count is specified.
The "maxgrow" command can be used to determine how much space can be added to an existing volume. This command respects volume layout device restrictions.
Example Section:
Maximum volumesize: 8314880 (4060Mb) The available size has changed for the above example from 6090Mb (concat layout) to 4060Mb for the striped volume layout. The default stripe column count is 2 columns, when no column count is specified.
The "maxgrow" command can be used to determine how much space can be added to an existing volume. This command respects volume layout device restrictions.
Example Section:
# vxassist -g tdg make tvol 1000M layout=striped ncols=3
# vxprint -htqg tdg
dgtdg default default 0 1262975382.14.therat dmdisk01 sdb auto 2074 4158112 - dmdisk02 sdc auto 2074 4158112 - dmdisk03 sdd auto 2074 4158112 - v tvol - ENABLED ACTIVE 2048000 SELECT tvol-01 fsgen pltvol-01 tvol ENABLED ACTIVE 2048256 STRIPE 3/128 RW sddisk01-01 tvol-01 disk01 0 682752 0/0 sdb ENA sddisk02-01 tvol-01 disk02 0 682752 1/0 sdc ENA sddisk03-01 tvol-01 disk03 0 682752 2/0 sdd ENA To determine how much space is left available for a concat volume (total free space in disk group):
# vxassist -g tdg maxsize
To determine how much space is left available for a new 2 column stripe volume:
Maximum volume size: 10424320(5090Mb) To determine how much space is left available for a new 2 column stripe volume:
# vxassist -g tdg maxsize layout=striped ncols=2
To determine how much the existing volume 'tvol' can be grown:
Maximum volume size: 6948864(3393Mb) To determine how much the existing volume 'tvol' can be grown:
# vxassist -g tdg maxgrow tvol
Volume tvol can be extended by10424320 to: 12472320 (6090Mb) Issue/Introduction
How to determine free space in a disk group using the vxassist maxsize and maxgrow commands
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