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Does Infoscale Storage (VVR) support cascaded space-optimized snapshot?

martinfrancis
Level 3

Configuration: Infoscale Storage 8.0 on Linux

Infoscale storage foundation supports cascaded snapshot using vxsnap infrontof= to do cascaded snapshots

Infoscale storage (with Volume replicator) documentation doesn't describe cascaded snapshot.
I checked manpage for vxrvg. Does not have an infront of attribute.
Does that mean cascaded space-optimized snapshots are not supported/permitted on RVG?

2 REPLIES 2

sdighe1
Level 3
Employee

Hi Martin,

The option is expected to work on VVR deployments too. Just that specific documentation is not done because the infrontof option is not VVR specific. You can the same on your lab. I did try out in my system, and working fine.

vradmin -g dg1 repstatus myrvg

Replicated Data Set: myrvg

Primary:

  Host name:                  192.168.20.93

  RVG name:                   myrvg

  DG name:                    dg1

  RVG state:                  enabled for I/O

  RVG encrypted:              No

  Data volumes:               1

  VSets:                      0

  SRL name:                   srlvol

  SRL size:                   1.00 T

  Total secondaries:          1

Secondary:

  Host name:                  192.168.20.94

  RVG name:                   myrvg

  DG name:                    dg1

  Data status:                consistent, up-to-date

  Replication status:         replicating (connected)

  Current mode:               N/A

  Logging to:                 SRL

  Timestamp Information:      behind by  0h 0m 0s

Created few snapshots

vxsnap -g dg1 make source=vol1/new=vol1_snap1/cachesize=100g

vxsnap -g dg1 make source=vol1/new=vol1_snap2/cache=vol1_snap1-C01/infrontof=vol1_snap1

vxsnap -g dg1 make source=vol1/new=vol1_snap3/cache=vol1_snap1-C01/infrontof=vol1_snap2

vxsnap -g dg1 make source=vol1/new=vol1_snap4/cache=vol1_snap1-C01/infrontof=vol1_snap3

vxsnap -g dg1 list

NAME          DG         OBJTYPE SNAPTYPE PARENT     PARENTDG   SNAPDATE

vol1          dg1        vol     -        -          -          - -             

vol1_snap1    dg1        vol     spaceopt vol1       dg1        2023/05/30 07:18

vol1_snap2    dg1        vol     spaceopt vol1       dg1        2023/05/30 07:18

vol1_snap3    dg1        vol     spaceopt vol1       dg1        2023/05/30 07:18

vol1_snap4    dg1        vol     spaceopt vol1       dg1        2023/05/30 07:19

 

vxsnap -g dg1 print

NAME    SNAPOBJECT    TYPE    PARENT    SNAPSHOT    %DIRTY    %VALID

vol1     --           volume   --       --           --       100.00

vol1_snap1_snp  volume   --       vol1_snap1   0.00     --    

vol1_snap2_snp  volume   --       vol1_snap2   0.00     --    

vol1_snap3_snp  volume   --       vol1_snap3   0.00     --    

vol1_snap4_snp  volume   --       vol1_snap4   0.00     --    

vol1_snap1 vol1_snp     volume   vol1     --           0.00     0.00  

vol1_snap2 vol1_snp1    volume   vol1     --           0.00     0.00  

vol1_snap3 vol1_snp2    volume   vol1     --           0.00     0.00  

vol1_snap4 vol1_snp3    volume   vol1     --           0.00     0.00  

thanks for verifying that  vxsnap option works with "infrontof" on VVR secondary volumes.
So are you suggesting that:
1) If I want to use cascaded snaps on VVR secondary I should use "vxsnap" command.
In all other type of snaps (space optimized, instant full, plex breakoff) I should use vxrvg?

2) Why doesn't vxrvg support "infrontof" attribute while it supports all other types of snap? [not just documentation, even the command vxrvg snapshot doesn't have an option for infrontof]

3) If there is no difference between vxsnap snapshot and vxrvg snapshot, why does vxrvg snapshot command exist. So I am thinking what would I be missing if I use vxsnap snapshot command instead of vxrvg snapshot