vxsnap prepare fails for FSS (Flexible Storage Sharing) with VVR (Veritas Volume Replicator) requires ndcomirs=2 option
Article ID: 100054859
Updated On:
Description
Error Message
In this instance, the FSS related disk group is named "fssdg".
The following vxsnap syntax fails when attempting to prepare the DCO log for VVR replicated data volume "vol1".
# vxsnap -g fssdg prepare vol1
VxVM vxsnap INFO V-5-1-13571 Volume is under RVG, setting drl=no.
VxVM vxassist ERROR V-5-1-18825 Cannot allocate space for 67840 block for DCO log volume for FSS dg: Not enough HDD devices that meet specification.
Cause
Even though sufficient space is free and readily available in the impacted disk group, the vxsnap prepare command fails.
# vxdg -g fssdg free
DISK DEVICE TAG OFFSET LENGTH FLAGS
emc0_dd6 emc0_dd6 emc0_dd6 3145792 7265984 -
emc0_dd7 emc0_dd7 emc0_dd7 1024000 9387776 -
emc0_dd8 emc0_dd8 emc0_dd8 0 954112 -
3pardata0_55 3pardata0_55 3pardata0_55 3145792 67776 -
3pardata0_55 3pardata0_55 3pardata0_55 3283456 836864 -
3pardata0_57 3pardata0_57 3pardata0_57 64 954048 -
The Veritas Volume Manager (VxVM) code requires the ndcomirs argument to be specified due to the number of plexes for the VVR replicated data volume "vol1".
The following vxsnap prepare command works if you specify the number of DCO mirrors (ndcomirs=2):
# vxsnap -g fssdg prepare vol1 ndcomirs=2 alloc="emc0_dd8,3pardata0_57"
VxVM vxsnap INFO V-5-1-13571 Volume is under RVG, setting drl=no.
Sample vxprint output
rv rvg 1 ENABLED ACTIVE secondary 1 srl
rl to_server rvg DETACHED STALE xxx.xxx.xx.xxx fssdg to_drserver
v vol1 rvg ENABLED ACTIVE 3145728 SELECT - fsgen
pl vol1-01 vol1 ENABLED ACTIVE 3145728 CONCAT - RW
sd emc0_dd6-01 vol1-01 emc0_dd6 0 3145728 0 emc0_dd6 ENA
pl vol1-02 vol1 ENABLED ACTIVE 3145728 CONCAT - RW
sd 3pardata0_54-01 vol1-02 3pardata0_54 0 3145728 0 3pardata0_54 ENA
pl vol1-03 vol1 ENABLED ACTIVE LOGONLY CONCAT - RW
sd emc0_dd6-03 vol1-03 emc0_dd6 3213568 64 LOG emc0_dd6 ENA
pl vol1-04 vol1 ENABLED ACTIVE LOGONLY CONCAT - RW
sd emc0_dd7-02 vol1-04 emc0_dd7 1024000 64 LOG emc0_dd7 ENA
dc vol1_dco vol1 vol1_dcl
v vol1_dcl - ENABLED ACTIVE 67840 SELECT - gen
pl vol1_dcl-01 vol1_dcl ENABLED ACTIVE 67840 CONCAT - RW
sd emc0_dd6-02 vol1_dcl-01 emc0_dd6 3145728 67840 0 emc0_dd6 ENA
pl vol1_dcl-02 vol1_dcl ENABLED ACTIVE 67840 CONCAT - RW
sd 3pardata0_54-02 vol1_dcl-02 3pardata0_54 3145728 67840 0 3pardata0_54 ENA
v srl rvg ENABLED ACTIVE 1024000 SELECT - SRL
pl srl-01 srl ENABLED ACTIVE 1024000 CONCAT - RW
sd emc0_dd7-01 srl-01 emc0_dd7 0 1024000 0 emc0_dd7 ENA
pl srl-02 srl ENABLED ACTIVE 1024000 CONCAT - RW
sd 3pardata0_55-01 srl-02 3pardata0_55 0 1024000 0 3pardata0_55 ENA
In this instance, the volume "vol1" has 2 x DATA plexes and 2 x DCM log plexes.
The vxsnap code believes the default ndcomirs count should be "4", due to the number of plexes (4) associated with the data volume.
Resolution
Ensure the ndcomirs argument is defined when creating a DCO log for a VVR replicated data volumes created inside an "FSS" type disk group.
# vxsnap -g
Issue/Introduction
The vxsnap prepare operations fails when attempting to create a DCO (Data Change Object) for FSS (Flexible Storage Sharing) disk groups with VVR (Veritas Volume Replicator) volumes.
Sample: vxprint output
# vxprint -qhtg fssdg
dg fssdg default default 36000 1673279611.34.server101
dm emc0_dd6 emc0_dd6 auto 65536 10411776 REMOTE
dm emc0_dd7 emc0_dd7 auto 65536 10411776 REMOTE
dm emc0_dd8 emc0_dd8 auto 65536 954112 REMOTE
dm 3pardata0_54 3pardata0_54 auto 65536 4120320 -
dm 3pardata0_55 3pardata0_55 auto 65536 4120320 -
dm 3pardata0_56 3pardata0_56 auto 65536 954112 -
dm 3pardata0_57 3pardata0_57 auto 65536 954112 -
dm 3pardata0_58 3pardata0_58 auto 65536 954112 -
rv rvg 1 ENABLED ACTIVE primary 1 srl
rl to_drserver rvg DETACHED STALE xxx.xxx.xx.xxx fssdg to_server
v vol1 rvg ENABLED ACTIVE 3145728 SELECT - fsgen
pl vol1-01 vol1 ENABLED ACTIVE 3145728 CONCAT - RW
sd emc0_dd6-01 vol1-01 emc0_dd6 0 3145728 0 emc0_dd6 ENA
pl vol1-02 vol1 ENABLED ACTIVE 3145728 CONCAT - RW
sd 3pardata0_55-01 vol1-02 3pardata0_55 0 3145728 0 3pardata0_55 ENA
pl vol1-04 vol1 ENABLED ACTIVE LOGONLY CONCAT - RW
sd emc0_dd6-02 vol1-04 emc0_dd6 3145728 64 LOG emc0_dd6 ENA
pl vol1-05 vol1 ENABLED ACTIVE LOGONLY CONCAT - RW
sd 3pardata0_57-01 vol1-05 3pardata0_57 0 64 LOG 3pardata0_57 ENA
v srl rvg ENABLED ACTIVE 1024000 SELECT - SRL
pl srl-01 srl ENABLED ACTIVE 1024000 CONCAT - RW
sd emc0_dd7-01 srl-01 emc0_dd7 0 1024000 0 emc0_dd7 ENA
pl srl-02 srl ENABLED ACTIVE 1024000 CONCAT - RW
sd 3pardata0_55-03 srl-02 3pardata0_55 3213568 69888 0 3pardata0_55 ENA
sd 3pardata0_56-01 srl-02 3pardata0_56 0 954112 69888 3pardata0_56 ENA