How to convert a mirror-stripe volume to a stripe-mirror.

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TechNote ID: 233797 Last Updated: January 20 2001 01:21 AM GMT
How to convert a mirror-stripe volume to a stripe-mirror.

Solution:

VERITAS Volume Manager 3.0 or higher allows subdisks to be built on volumes.This layered volume structure to lerates failure better and has greater redundancy than the standard volume structure. Building a stripe-mirror volume (a.k.a.. stripe-pro), a failing subdisk holding a stripe column no longer means loss of that entire plex. Each column is mirrored at the subdisk level, so only that subdisk needs to be resynchronized after drive replacement as opposed to the full plex.
To take advantage of layered volumes, a mirror-stripe volume can be converted to a stripe-mirror using the vxassist convert command.

For Example:

# vxassist -g test_dg make vol01 2000m layout=mirror-stripe
 # vxprint -htr -g test_dg
v  vol01        -             ENABLED  ACTIVE   4096000  fsgen     -         SELECT
pl vol01-01     vol01        ENABLED   ACTIVE   4108944  STRIPE    4/128    RW
sd test_dg08-01 vol01-01     test_dg08 0       1027216  0/0       c1t1d0   ENA
sd test_dg09-01 vol01-01     test_dg09 0       1027216  1/0       c1t2d0   ENA
sd test_dg03-01 vol01-01     test_dg03 0       1025136  2/0       c1t3d0   ENA
sd test_dg04-01 vol01-01     test_dg04 0       1025136  3/0       c1t4d0   ENA
pl vol01-02     vol01        ENABLED  ACTIVE   4100592  STRIPE    4/128    RW
sd test_dg05-01 vol01-02     test_dg05 0       1025136  0/0       c2t1d0   ENA
sd test_dg06-01 vol01-02     test_dg06 0       1025136  1/0       c2t2d0   ENA
sd test_dg07-01 vol01-02     test_dg07 0       1025136  2/0       c2t3d0   ENA
sd test_dg01-01 vol01-02     test_dg01 0       1025136  3/0       c2t4d0   ENA

Shows vol01 as a mirrored stripe volume. This was common prior to release 3.0.

To convert this to a stripe-pro volume:

# vxassist -g test_dg convert vol01 layout=stripe-mirror
# vxprint -htr -g test_dg
 v  vol01        -            ENABLED   ACTIVE   4096000  fsgen     vol01-03 SELECT
pl vol01-03     vol01         ENABLED  ACTIVE   4096000  STRIPE    4/128    RW

sv vol01-S01    vol01-03     vol01-L01 1       1024000  0/0       2/2      ENA
v2 vol01-L01    -            ENABLED  ACTIVE   1024000   fsgen     -        SELECT
p2 vol01-P01    vol01-L01     ENABLED  ACTIVE   1024000  CONCAT    -        RW
s2 test_dg08-02 vol01-P01    test_dg08 0       1024000  0         c1t1d0   ENA
p2 vol01-P02    vol01-L01    ENABLED  ACTIVE   1024000   CONCAT    -        RW
s2 test_dg05-02 vol01-P02    test_dg05 0       1024000  0         c2t1d0   ENA

sv vol01-S02    vol01-03     vol01-L02 1       1024000  1/0       2/2      ENA
v2 vol01-L02    -            ENABLED  ACTIVE   1024000  fsgen     -        SELECT
p2 vol01-P03    vol01-L02    ENABLED  ACTIVE   1024000   CONCAT    -        RW
s2 test_dg09-02 vol01-P03    test_dg09 0       1024000  0         c1t2d0   ENA
p2 vol01-P04    vol01-L02     ENABLED  ACTIVE   1024000  CONCAT    -        RW
s2 test_dg06-02 vol01-P04    test_dg06 0       1024000  0         c2t2d0   ENA

sv vol01-S03    vol01-03     vol01-L03 1       1024000   2/0       2/2      ENA
v2 vol01-L03    -            ENABLED  ACTIVE   1024000  fsgen     -         SELECT
p2 vol01-P05    vol01-L03    ENABLED  ACTIVE   1024000  CONCAT    -        RW
s2 test_dg03-03 vol01-P05    test_dg03 0       1024000   0         c1t3d0   ENA
p2 vol01-P06    vol01-L03    ENABLED   ACTIVE   1024000  CONCAT    -        RW
s2 test_dg07-02 vol01-P06    test_dg07 0       1024000  0         c2t3d0   ENA

sv vol01-S04    vol01-03     vol01-L04 1       1024000  3/0       2/2      ENA
v2 vol01-L04    -            ENABLED  ACTIVE   1024000  fsgen     -         SELECT
p2 vol01-P07    vol01-L04    ENABLED  ACTIVE   1024000  CONCAT    -        RW
s2 test_dg04-02 vol01-P07    test_dg04 0       1024000  0         c1t4d0   ENA
p2 vol01-P08    vol01-L04    ENABLED  ACTIVE   1024000  CONCAT    -        RW
s2 test_dg01-02 vol01-P08    test_dg01 0       1024000  0         c2t4d0   ENA

The output shows that vol01 is a volume holding 4 subvolumes. Each subvolume represents one column of the stripe. The subvolumes in this example are mirrored, displaying the additional redundancy.

NOTE: There is no data moved. The vxassist convert is almost immediate.

Products:
Volume Manager for UNIX   3.0, 3.0.1, 3.0.2, 3.0.2.1, 3.0.3, 3.0.4
Subject: Application - Configuration
Application - Device Management
Application - How To
A pplication - Informational
Languages: English
Operating Systems:
Solaris   2.5.1, 2.6, 7
E-Mail for Classic Seagate Software Products: helpdesk@support.ve ritas.com
FTP:ftp://ftp.support.veritas.com or http://ftp.support.veritas.com

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