Error Message

When the "vxassist relayout" command fails to handle a relayout transformation, it may just print an error and doesn't perform the transformation. For example, transforming a concat-mirror volume to a concat volume is not permitted using "vxassist relayout"

# vxassist -g tdg make vol_concat_mirror 100m layout=concat-mirror init=active

v vol_concat_mirror - ENABLED ACTIVE 204800 SELECT - fsgen
pl vol_concat_mirror-03 vol_concat_mirror ENABLED ACTIVE 204800 CONCAT - RW
sv vol_concat_mirror-S01 vol_concat_mirror-03 vol_concat_mirror-L01 1 204800 0 2/2 ENA
v2 vol_concat_mirror-L01 - ENABLED ACTIVE 204800 SELECT - fsgen
p2 vol_concat_mirror-P01 vol_concat_mirror-L01 ENABLED ACTIVE 204800 CONCAT - RW
s2 tdg07-03 vol_concat_mirror-P01 tdg07 102400 204800 0 virtio0_9 ENA
p2 vol_concat_mirror-P02 vol_concat_mirror-L01 ENABLED ACTIVE 204800 CONCAT - RW
s2 tdg09-03 vol_concat_mirror-P02 tdg09 102400 204800 0 virtio0_14 ENA

# vxassist -g tdg relayout vol_concat_mirror layout=concat
VxVM vxassist INFO V-5-1-2140 This operation is not a relayout -- trying convert

For some other unsupported transformation requests, "vxassist relayout" may just transform the volume to a supported layout resembling the requested layout and require the user to perform the final transformation using the 'vxassist convert" command. For example,

1. Create a stripe-mirror

# vxassist -g tdg make volgreen 100m layout=stripe-mirror ncolumn=2 init=active

v volgreen - ENABLED ACTIVE 204800 SELECT volgreen-03 fsgen
pl volgreen-03 volgreen ENABLED ACTIVE 204800 STRIPE 2/128 RW <<< stripe-mirror
sv volgreen-S01 volgreen-03 volgreen-L01 1 102400 0/0 2/2 ENA
v2 volgreen-L01 - ENABLED ACTIVE 102400 SELECT - fsgen
p2 volgreen-P01 volgreen-L01 ENABLED ACTIVE 102400 CONCAT - RW
s2 tdg06-03 volgreen-P01 tdg06 102400 102400 0 virtio0_7 ENA
p2 volgreen-P02 volgreen-L01 ENABLED ACTIVE 102400 CONCAT - RW
s2 tdg08-03 volgreen-P02 tdg08 102400 102400 0 virtio0_11 ENA
sv volgreen-S02 volgreen-03 volgreen-L02 1 102400 1/0 2/2 ENA
v2 volgreen-L02 - ENABLED ACTIVE 102400 SELECT - fsgen
p2 volgreen-P03 volgreen-L02 ENABLED ACTIVE 102400 CONCAT - RW
s2 tdg07-03 volgreen-P03 tdg07 102400 102400 0 virtio0_9 ENA
p2 volgreen-P04 volgreen-L02 ENABLED ACTIVE 102400 CONCAT - RW
s2 tdg09-03 volgreen-P04 tdg09 102400 102400 0 virtio0_14 ENA

2. Trying to relayout it to mirror-concat volume but result in only a concat-mirror volume

# vxassist -g tdg relayout volgreen layout=mirror-concat

v volgreen - ENABLED ACTIVE 204800 SELECT - fsgen
pl volgreen-03 volgreen ENABLED ACTIVE 204800 CONCAT - RW <<< a concat-mirror is generated instead
sv volgreen-Ds01 volgreen-03 volgreen-d01 1 204800 0 2/2 ENA
v2 volgreen-d01 - ENABLED ACTIVE 204800 SELECT - fsgen
p2 volgreen-dp01 volgreen-d01 ENABLED ACTIVE 204800 CONCAT - RW
s2 tdg06-05 volgreen-dp01 tdg06 102400 204800 0 virtio0_7 ENA
p2 volgreen-dp02 volgreen-d01 ENABLED ACTIVE 204800 CONCAT - RW
s2 tdg08-05 volgreen-dp02 tdg08 102400 204800 0 virtio0_11 ENA

3. Need to run "vxassist convert" to convert the volume to the required mirror-concat layout.

# vxassist -g tdg convert volgreen layout=mirror-concat

v volgreen - ENABLED ACTIVE 204800 SELECT - fsgen
pl volgreen-01 volgreen ENABLED ACTIVE 204800 CONCAT - RW
sd tdg06-01 volgreen-01 tdg06 102400 204800 0 virtio0_7 ENA
pl volgreen-02 volgreen ENABLED ACTIVE 204800 CONCAT - RW
sd tdg08-01 volgreen-02 tdg08 102400 204800 0 virtio0_11 ENA

It is a current design limitation of the VxVM online relayout feature.

Please observe the limitation as documented in the Veritas Storage Foundation Administrator's Guide and follow the recommendation to achieve the required layout transformation if it is supported.

Side Notes
========
Currently the Table 30-3 in the SF Admin Guide is incorrect.   Table 30-3 is supposed to list the supported relyaout transformation for RAID-5 volume, but the current document incorrectly listed the one for mirrored-stripe volumes.   A documentation etrack is created to correct it.

Applies To

The online relayout limitation is applicable to all VxVM supported platforms.   Please refer to the Veritas Storage Foundation Administrator's Guide of individual platform for details.

VxVM online relayout is performed by using the "vxassist relayout" command. There are some limitations on the capability of online relayout. Details of those limitations are listed in Veritas Storage Foundation Administrator's Guide. For example, in the Veritas Storage Foundation 6.0.1 Administrator's Guide for Solaris, the permitted relayout transformations are listed in page 606. Veritas Storage Foundation product documents can be downloaded from the Veritas Operation Readiness Tools website. https://docs.infoscale.com/documents/ The following is the SF 6.0.1 Admin Guide for Solaris. https://docs.infoscale.com/support/en_US/doc/ka6j0000000BNdAAAW

On page 635 there is the section on "Permitted relayout transformation".

ETrack: 3311862