Striped volumes must have enough devices and free space to grow all columns in parallel

Striped volumes must have enough devices and free space to grow all columns in parallel

  • Article ID:100029664
  • Last Published:
  • Product(s):InfoScale & Storage Foundation

Problem

Striped volumes must have enough devices and free space to grow all columns in parallel

Solution

Volume Manager has the following internal restrictionsregarding the extension of striped volume columns:

  • Device(s)used in one column cannot be used in any other columns in that volume
  • Allstripe columns must be grown in parallel

Usethe following commands to determine if you have enough devices or free space togrow your volume.

# vxprint -htqg datadgexamplevol
v  examplevol  -            ENABLED  ACTIVE   117463040SELECT   examplevol-01 fsgen
pl examplevol-01examplevol  ENABLED  ACTIVE   117463296 STRIPE  3/128    RW
sd d01-01       examplevol-01d01     0        39154432 0/0      c4t0d1   ENA
sd d02-01       examplevol-01d02     0        39154432 1/0      c4t0d2   ENA
sd d03-01       examplevol-01d03     0        39154432 2/0      c4t0d3   ENA

The above volume is a 3 column stripe volume.  Youcan determine this by examining the plex line following STRIPE where you can see 3/128 .  This value is shown inCOLUMNS/STRIPE_WIDTH format.

The disk group in this example contains thefollowing devices:

dmd01          c4t0d1      auto     2048     60126464-
dmd02          c4t0d2      auto     2048     60126464-
dmd03          c4t0d3      auto     2048     60126464-
dmd04          c4t0d4      auto     2048     60126464 -

Attemptingto grow this volume using only the currently available devices will produce thefollowing error:

# /etc/vx/bin/vxresize -gdatadg examplevol +1g
VxVM vxassistERROR V-5-1-436 Cannot allocate space to grow volume to 119560192blocks
VxVM vxresize ERROR V-5-1-4703Problem running vxassist command for volume examplevol, in diskgroupdatadg

You can also predetermine how much space Volume Managecan extend your volume by using the followingcommand:
# vxassist -g <dg> maxgrow<volume>

In this example, the following is theresult:
# vxassist -g datadg maxgrowexamplevol
VxVM vxassist ERRORV-5-1-1178 Volume examplevol cannot be extend within the givenconstraints

Because VM requires a unique device for eachstripe, and there is only one device available for the three column volume, thegrow operation cannot run.

To resolve this issue you must add enoughstorage devices to satisfy the above constraints or use a relayout operation toconvert the volume's column count.  For additional information onperforming a relayout operation see the supplemental material below.

Inthe example, two additional devices have been added to the diskgroup:

dmd01          c4t0d0      auto     2048     60126464-
dmd02          c4t0d1      auto     2048     60126464-
dmd03          c4t0d2      auto     2048     60126464-
dmd04          c4t0d3      auto     2048     60126464-
dmd05          c4t0d4      auto     2048     60126464-
dmd06          c4t0d5      auto     2048     60126464 -

And theresize operation completes withoutcomplaint:

# /etc/vx/bin/vxresize -g datadgexamplevol +1g
# vxprint -htqg datadgexamplevol

v  examplevol  -            ENABLED  ACTIVE   119560192SELECT   examplevol-01 fsgen
plexamplevol-01 examplevol  ENABLED  ACTIVE   119560320STRIPE  3/128    RW
sdd01-01       examplevol-01 d01    0        391544320/0        c4t0d1  ENA
sdd04-01       examplevol-01 d04    0        699008   0/39154432c4t0d4  ENA
sdd02-01       examplevol-01 d02    0        391544321/0        c4t0d2  ENA
sdd05-01       examplevol-01 d05    0        699008   1/39154432c4t0d5  ENA
sdd03-01       examplevol-01 d03    0        391544322/0        c4t0d3  ENA
sdd06-01       examplevol-01 d06    0        699008   2/39154432c4t0d6  ENA


Was this content helpful?