Description

The following procedure explains how to prevent the standard vxassist command operation from creating a layered volumes.

When a volume is grown or initially created, its layout may adopt or be converted as a side effect to a layered structure.
 

The following command creates a 1g layered stripe-mirrored volume layout.
 

# vxassist -g testdg make vol01 1g layout=stripe,mirror mirror=enclosure

# vxprint -qhtg testdg
dg testdg       default      default  2000     1582025610.49.gpk630r4c-07

dm hitachi_vspgx0_025b hitachi_vspgx0_025b auto 65536 209639920 -
dm hitachi_vspgx0_025c hitachi_vspgx0_025c auto 65536 209639920 -
dm hitachi_vspgx0_025d hitachi_vspgx0_025d auto 65536 209639920 -
dm hitachi_vspgx1_0000 hitachi_vspgx1_0000 auto 65536 209639920 -
dm hitachi_vspgx1_000b hitachi_vspgx1_000b auto 65536 209639920 -
dm hitachi_vspgx1_0001 hitachi_vspgx1_0001 auto 65536 209639920 -

v  vol01        -            ENABLED  ACTIVE   2097152  SELECT    -        fsgen
pl vol01-03     vol01        ENABLED  ACTIVE   2097408  STRIPE    3/128    RW
sv vol01-S01    vol01-03     vol01-L01 1       699136   0/0       2/2      ENA
sv vol01-S02    vol01-03     vol01-L02 1       699136   1/0       2/2      ENA
sv vol01-S03    vol01-03     vol01-L03 1       699136   2/0       2/2      ENA
dc vol01_dco    vol01        vol01_dcl
v  vol01_dcl    -            ENABLED  ACTIVE   67840    SELECT    -        gen
pl vol01_dcl-01 vol01_dcl    ENABLED  ACTIVE   67840    CONCAT    -        RW
sd hitachi_vspgx0_025b-03 vol01_dcl-01 hitachi_vspgx0_025b 699136 67840 0 hitachi_vspgx0_025b ENA
pl vol01_dcl-02 vol01_dcl    ENABLED  ACTIVE   67840    CONCAT    -        RW
sd hitachi_vspgx1_0000-03 vol01_dcl-02 hitachi_vspgx1_0000 699136 67840 0 hitachi_vspgx1_0000 ENA

v  vol01-L01    -            ENABLED  ACTIVE   699136   SELECT    -        fsgen
pl vol01-P01    vol01-L01    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx0_025b-02 vol01-P01 hitachi_vspgx0_025b 0 699136 0 hitachi_vspgx0_025b ENA
pl vol01-P02    vol01-L01    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx1_0000-02 vol01-P02 hitachi_vspgx1_0000 0 699136 0 hitachi_vspgx1_0000 ENA

v  vol01-L02    -            ENABLED  ACTIVE   699136   SELECT    -        fsgen
pl vol01-P03    vol01-L02    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx0_025c-02 vol01-P03 hitachi_vspgx0_025c 0 699136 0 hitachi_vspgx0_025c ENA
pl vol01-P04    vol01-L02    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx1_000b-02 vol01-P04 hitachi_vspgx1_000b 0 699136 0 hitachi_vspgx1_000b ENA

v  vol01-L03    -            ENABLED  ACTIVE   699136   SELECT    -        fsgen
pl vol01-P05    vol01-L03    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx0_025d-02 vol01-P05 hitachi_vspgx0_025d 0 699136 0 hitachi_vspgx0_025d ENA
pl vol01-P06    vol01-L03    ENABLED  ACTIVE   699136   CONCAT    -        RW
sd hitachi_vspgx1_0001-02 vol01-P06 hitachi_vspgx1_0001 0 699136 0 hitachi_vspgx1_0001 ENA

 

NOTE: If vxassist determines that the new volume is too large for the original layout, a layered volume layout is adopted.


The values of the stripe-mirror-col-trigger-pt and stripe-mirror-col-split-trigger-pt attributes (by default, 1 gigabyte) control whether a new layout will be applied.

stripe-mirror-col-trigger-pt=size

Specifies a size that triggers the creation of a stripe-mirror volume. If the size of the volume is greater than the size specified in this attribute, then a stripe-mirror volume is created.

stripe-mirror-col-split-trigger-pt=size

Specifies a size that triggers the creation of a stripe-mirror-sd volume. If the size of each column is greater than the size specified in this attribute, then a stripe-mirror-sd volume is created.

stripe_stripeunit=width 

Prevent layered volume creation

It is possible to prevent the creation and modification of an existing volume when resized, by populating the /etc/default/vxassist file with two key attributes.

# cat /etc/default/vxassist
stripe-mirror-col-trigger-pt=262144g
stripe-mirror-col-split-trigger-pt=262144g
 

Convert back to non-layered layout
 

The layered layout can be converted back to a non-layered layout using the convert option with vxassist:

# vxassist -g testdg convert vol01 layout=mirror-stripe

# vxprint -qhtg testdg
dg testdg       default      default  2000     1582025610.49.gpk630r4c-07

dm hitachi_vspgx0_025b hitachi_vspgx0_025b auto 65536 209639920 -
dm hitachi_vspgx0_025c hitachi_vspgx0_025c auto 65536 209639920 -
dm hitachi_vspgx0_025d hitachi_vspgx0_025d auto 65536 209639920 -
dm hitachi_vspgx1_0000 hitachi_vspgx1_0000 auto 65536 209639920 -
dm hitachi_vspgx1_000b hitachi_vspgx1_000b auto 65536 209639920 -
dm hitachi_vspgx1_0001 hitachi_vspgx1_0001 auto 65536 209639920 -

v  vol01        -            ENABLED  ACTIVE   2097152  SELECT    -        fsgen
pl vol01-01     vol01        ENABLED  ACTIVE   2097408  STRIPE    3/128    RW
sd hitachi_vspgx0_025b-01 vol01-01 hitachi_vspgx0_025b 0 699136 0/0 hitachi_vspgx0_025b ENA
sd hitachi_vspgx0_025c-01 vol01-01 hitachi_vspgx0_025c 0 699136 1/0 hitachi_vspgx0_025c ENA
sd hitachi_vspgx0_025d-01 vol01-01 hitachi_vspgx0_025d 0 699136 2/0 hitachi_vspgx0_025d ENA
pl vol01-02     vol01        ENABLED  ACTIVE   2097408  STRIPE    3/128    RW
sd hitachi_vspgx1_0000-01 vol01-02 hitachi_vspgx1_0000 0 699136 0/0 hitachi_vspgx1_0000 ENA
sd hitachi_vspgx1_000b-01 vol01-02 hitachi_vspgx1_000b 0 699136 1/0 hitachi_vspgx1_000b ENA
sd hitachi_vspgx1_0001-01 vol01-02 hitachi_vspgx1_0001 0 699136 2/0 hitachi_vspgx1_0001 ENA
dc vol01_dco    vol01        vol01_dcl
v  vol01_dcl    -            ENABLED  ACTIVE   67840    SELECT    -        gen
pl vol01_dcl-01 vol01_dcl    ENABLED  ACTIVE   67840    CONCAT    -        RW
sd hitachi_vspgx0_025b-03 vol01_dcl-01 hitachi_vspgx0_025b 699136 67840 0 hitachi_vspgx0_025b ENA
pl vol01_dcl-02 vol01_dcl    ENABLED  ACTIVE   67840    CONCAT    -        RW
sd hitachi_vspgx1_0000-03 vol01_dcl-02 hitachi_vspgx1_0000 699136 67840 0 hitachi_vspgx1_0000 ENA