Table of ContentsView in Frames

Examples of deleting backing Snapshot copies of deleted LUN clones

You can use the snapshot_clone_dependency option to determine whether you can delete the base Snapshot copy without deleting the more recent Snapshot copies after deleting a LUN clone. This option is set to off by default.

Example with snapshot_clone_dependency set to off

The following example illustrates how all newer backing Snapshot copies must be deleted before deleting the base Snapshot copy when a LUN clone is deleted.

You can set the snapshot_clone_dependency option to off by entering the following command:

vol options volume_name snapshot_clone_dependency off

You can create a new LUN clone, lun_s1 from the LUN in Snapshot copy snap1. Also, you should run the lun show -v command to show that lun_s1 is backed by snap1.

system1> lun clone create /vol/vol1/lun_s1 -b /vol/vol1/lun snap1

system1>lun show -v
/vol/vol1/lun_s1  32m (33554432)  (r/w, online)
       Serial#: BYjB3?-iq3hU
       Backed by: /vol/vol1/.snapshot/snap1/lun
       Share: none
       Space Reservation: enabled
       Multiprotocol Type: linux
       Occupied Size:       0 (0)
       Creation Time: Tue Oct 19 10:49:13 GMT 2010
       Cluster Shared Volume Information: 0x0

You should run the snap list command to show that snap1 is busy, as expected.

system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 24% (24%)    0% ( 0%)  Dec 20 02:40  snap1          (busy,LUNs)

When you create a new Snapshot copy, snap2, it contains a copy of lun_s1, which is still backed by the LUN in snap1.

system1> snap create vol1 snap2
system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 24% (24%)    0% ( 0%)  Dec 20 02:41  snap2
 43% (31%)    0% ( 0%)  Dec 20 02:40  snap1          (busy,LUNs)

You should run the lun snap usage command to show this dependency.

system1> lun snap usage vol1 snap1
Active:
        LUN: /vol/vol1/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun
Snapshot - snap2:
        LUN: /vol/vol1/.snapshot/snap2/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun

Then you should delete the LUN clone lun_s1.

system1> lun destroy /vol/vol1/lun_s1
Wed Dec 20 02:42:23 GMT [wafl.inode.fill.disable:info]: fill reservation disabled for inode 3087 (vol vol1).
Wed Dec 20 02:42:23 GMT [wafl.inode.overwrite.disable:info]: overwrite reservation disabled for inode 3087 (vol vol1).
Wed Dec 20 02:42:23 GMT [lun.destroy:info]: LUN /vol/vol1/lun_s1 destroyed
system1> lun show
        /vol/vol1/lun                 30m (31457280)      (r/w, online)

You should run the lun snap usage command to show that snap2 still has a dependency on snap1.

system1> lun snap usage vol1 snap1
Snapshot - snap2:
        LUN: /vol/vol1/.snapshot/snap2/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun

You should run the snap list command to show that snap1 is still busy.

system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 39% (39%)    0% ( 0%)  Dec 20 02:41  snap2
 53% (33%)    0% ( 0%)  Dec 20 02:40  snap1          (busy, LUNs)

Since snap1 is still busy, you cannot delete it until you delete the more recent Snapshot copy, snap2.

Example with snapshot_clone_dependency set to on

The following example illustrates how you can delete a base Snapshot copy without deleting all newer backing Snapshot copies when a LUN clone is deleted.

You can set the snapshot_clone_dependency option to on by entering the following command:

vol options volume_name snapshot_clone_dependency on

You can create a new LUN clone, lun_s1, from the LUN in Snapshot copy snap1. You should run the lun show -v command to show that lun_s1 is backed by snap1.

system1> lun clone create /vol/vol1/lun_s1 -b /vol/vol1/lun snap1

system1> lun show -v
/vol/vol1/lun_s1  32m (33554432)  (r/w, online)
       Serial#: BYjB3?-iq3hU
       Backed by: /vol/vol1/.snapshot/snap1/lun
       Share: none
       Space Reservation: enabled
       Multiprotocol Type: linux
       Occupied Size:       0 (0)
       Creation Time: Tue Oct 19 10:49:13 GMT 2010
       Cluster Shared Volume Information: 0x0

You should run the snap list command to show that snap1 is busy, as expected.

system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 24% (24%)    0% ( 0%)  Dec 20 02:40  snap1          (busy,LUNs)

When you create a new Snapshot copy, snap2, it contains a copy of lun_s1, which is still backed by the LUN in snap1.

system1> snap create vol1 snap2
system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 24% (24%)    0% ( 0%)  Dec 20 02:41  snap2
 43% (31%)    0% ( 0%)  Dec 20 02:40  snap1          (busy,LUNs)

You should run the lun snap usage command to show this dependency.

system1> lun snap usage vol1 snap1
Active:
        LUN: /vol/vol1/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun
Snapshot - snap2:
        LUN: /vol/vol1/.snapshot/snap2/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun

Then you can delete the LUN clone lun_s1.

system1> lun destroy /vol/vol1/lun_s1
Wed Dec 20 02:42:23 GMT [wafl.inode.fill.disable:info]: fill reservation disabled for inode 3087 (vol vol1).
Wed Dec 20 02:42:23 GMT [wafl.inode.overwrite.disable:info]: overwrite reservation disabled for inode 3087 (vol vol1).
Wed Dec 20 02:42:23 GMT [lun.destroy:info]: LUN /vol/vol1/lun_s1 destroyed
system1> lun show
        /vol/vol1/lun                 30m (31457280)      (r/w, online)

You should run the lun snap usage command to show that snap2 still has a dependency on snap1.

system1> lun snap usage vol1 snap1
Snapshot - snap2:
        LUN: /vol/vol1/.snapshot/snap2/lun_s1
        Backed By: /vol/vol1/.snapshot/snap1/lun

You should run the snap list command to show that snap1 is no longer busy.

system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 39% (39%)    0% ( 0%)  Dec 20 02:41  snap2
 53% (33%)    0% ( 0%)  Dec 20 02:40  snap1

Since snap1 is no longer busy, you can delete it without first deleting snap2.

system1> snap delete vol1 snap1
Wed Dec 20 02:42:55 GMT [wafl.snap.delete:info]: Snapshot copy snap1 on volume vol1 was deleted by the Data ONTAP function snapcmd_delete.
The unique ID for this Snapshot copy is (1, 6).
system1> snap list vol1
Volume vol1
working...

  %/used       %/total  date          name
----------  ----------  ------------  --------
 38% (38%)    0% ( 0%)  Dec 20 02:41  snap2