An example will show in concrete terms how you can configure replication relationships one step at a time. You can use the vault-vault cascade deployment configured in the example to retain more than 251 Snapshot copies labeled “my-weekly”.

What you’ll need

The source and destination clusters and SVMs must be peered.
You must be running ONTAP 9.7 or later. Vault-vault cascades are not supported in earlier ONTAP releases.

About this task

The example assumes the following:

You have configured Snapshot copies on the source cluster with the SnapMirror labels “my-daily”, “my-weekly”, and “my-monthly”.
You have configured destination volumes named “volA” on the secondary and tertiary destination clusters.
You have configured replication job schedules named “my_snapvault” on the secondary and tertiary destination clusters.

The example shows how to create replication relationships based on two custom policies:

The “snapvault_secondary” policy retains 7 daily, 52 weekly, and 180 monthly Snapshot copies on the secondary destination cluster.
The “snapvault_tertiary policy” retains 250 weekly Snapshot copies on the tertiary destination cluster.

Steps

On the secondary destination cluster, create the “snapvault_secondary” policy:

cluster_secondary::> snapmirror policy create -policy snapvault_secondary -type vault -comment “Policy on secondary for vault to vault cascade” -vserver svm_secondary
On the secondary destination cluster, define the “my-daily” rule for the policy:

cluster_secondary::> snapmirror policy add-rule -policy snapvault_secondary -snapmirror-label my-daily -keep 7 -vserver svm_secondary
On the secondary destination cluster, define the “my-weekly” rule for the policy:

cluster_secondary::> snapmirror policy add-rule -policy snapvault_secondary -snapmirror-label my-weekly -keep 52 -vserver svm_secondary
On the secondary destination cluster, define the “my-monthly” rule for the policy:

cluster_secondary::> snapmirror policy add-rule -policy snapvault_secondary -snapmirror-label my-monthly -keep 180 -vserver svm_secondary

On the secondary destination cluster, verify the policy:

cluster_secondary::> snapmirror policy show snapvault_secondary -instance

                     Vserver: svm_secondary
      SnapMirror Policy Name: snapvault_secondary
      SnapMirror Policy Type: vault
                Policy Owner: cluster-admin
                 Tries Limit: 8
           Transfer Priority: normal
   Ignore accesstime Enabled: false
     Transfer Restartability: always
 Network Compression Enabled: false
             Create Snapshot: false
                     Comment: Policy on secondary for vault to vault cascade
       Total Number of Rules: 3
                  Total Keep: 239
                       Rules: SnapMirror Label     Keep  Preserve Warn Schedule Prefix
                              ----------------     ----  -------- ---- -------- ------
                              my-daily                7  false       0 -        -
                              my-weekly              52  false       0 -        -
                              my-monthly            180  false       0 -        -

On the secondary destination cluster, create the relationship with the source cluster:

cluster_secondary::> snapmirror create -source-path svm_primary:volA -destination-path svm_secondary:volA -type XDP -schedule my_snapvault -policy snapvault_secondary
On the secondary destination cluster, initialize the relationship with the source cluster:

cluster_secondary::> snapmirror initialize -source-path svm_primary:volA -destination-path svm_secondary:volA
On the tertiary destination cluster, create the “snapvault_tertiary” policy:

cluster_tertiary::> snapmirror policy create -policy snapvault_tertiary -type vault -comment “Policy on tertiary for vault to vault cascade” -vserver svm_tertiary
On the tertiary destination cluster, define the “my-weekly” rule for the policy:

cluster_tertiary::> snapmirror policy add-rule -policy snapvault_tertiary -snapmirror-label my-weekly -keep 250 -vserver svm_tertiary

On the tertiary destination cluster, verify the policy:

cluster_tertiary::> snapmirror policy show snapvault_tertiary -instance

                     Vserver: svm_tertiary
      SnapMirror Policy Name: snapvault_tertiary
      SnapMirror Policy Type: vault
                Policy Owner: cluster-admin
                 Tries Limit: 8
           Transfer Priority: normal
   Ignore accesstime Enabled: false
     Transfer Restartability: always
 Network Compression Enabled: false
             Create Snapshot: false
                     Comment: Policy on tertiary for vault to vault cascade
       Total Number of Rules: 1
                  Total Keep: 250
                       Rules: SnapMirror Label     Keep  Preserve Warn Schedule Prefix
                              ----------------     ----  -------- ---- -------- ------
                              my-weekly             250  false       0 -        -

On the tertiary destination cluster, create the relationship with the secondary cluster:

cluster_tertiary::> snapmirror create -source-path svm_secondary:volA -destination-path svm_tertiary:volA -type XDP -schedule my_snapvault -policy snapvault_tertiary
On the tertiary destination cluster, initialize the relationship with the secondary cluster:

cluster_tertiary::> snapmirror initialize -source-path svm_secondary:volA -destination-path svm_tertiary:volA