Snapshot naming enhancements in ONTAP 9.0

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Category:: ontap-9

Specialty:: core

Last Updated:

Applies to

ONTAP 9.0

Answer

In the classic Data ONTAP 7-Mode, snapshots were created with either ordinal names or create_time names.

With ordinal naming, the scheduled snapshot names were formatted with a schedule prefix and an ordinal number, where 0 represented the most recent snapshot taken.
For example, if the snapshot schedule used was nightly and the ordinal naming is used, then a new scheduled snapshot would have the name: "nightly.0".

With the 'create_time' naming, the scheduled snapshot names are formatted with a schedule prefix and a creation time.
In this case, the suffix would be a timestamp with the Y-m-d_HM format.

Users had the option to select either of the naming schemes by using the schedsnapname volume option.

See the following samples:

Using ordinal snapshots:

7mode-filer> vol options vol1 schedsnapname ordinal 7mode-filer> snap list vol1 Volume vol1 working... %/used %/total date name ---------- ---------- ------------ -------- 27% (27%) 0% ( 0%) Jun 23 08:00 hourly.0 27% (27%) 0% ( 0%) Jun 23 07:00 hourly.1 47% (33%) 0% ( 0%) Jun 23 00:00 nightly.0 67% (33%) 1% ( 0%) Jun 22 00:00 nightly.1 72% (33%) 1% ( 0%) Jun 19 20:00 weekly.0

Using create_time snapshots:

7mode-filer> vol options vol1 schedsnapname create_time 7mode-filer> snap list vol1 Volume vol1 working... %/used %/total date name ---------- ---------- ------------ -------- 27% (27%) 0% ( 0%) Jun 23 12:00 hourly.2016-06-23_1200 27% (27%) 0% ( 0%) Jun 23 07:00 hourly.2016-06-23_0700 47% (33%) 0% ( 0%) Jun 23 00:00 nightly.2016-06-23_0000 67% (33%) 1% ( 0%) Jun 22 00:00 nightly.2016-06-22_0000 72% (33%) 1% ( 0%) Jun 19 00:00 weekly.2016-06-19_0000

When clustered Data ONTAP was introduced, the 'create_time' naming convention was adopted as the default and the only option due to various reasons.
Any attempt to change snapshot naming resulted in an error message similar to the following:

cluster::> vol modify -volume vol1 -sched-snap-name ordinal -vserver vsm1 (volume modify) Error: command failed: Option sched-snap-name is not supported on a cluster mode volume. cluster::>

ONTAP 9 changes:

Removing the ordinal name scheme of snapshots in clustered Data ONTAP created an issue with applications relying on ordinal naming scheme and an RFE 821993 was filed.
In ONTAP 9.0, the sched-snap-name option is introduced again and can be enabled by the vol modify command.

Moreover, the snapshot naming change for cluster mode volumes are applied at the cluster M-Host level only and is not applied at the nodeshell D-Blade level.
So after changing the sched-snap-name at the cluster level to ordinal, the nodeshell (D-Blade) will still display the default 'create_time' and it is an expected behavior.

cluster::> vol modify vol1 -sched-snap-name ordinal Volume modify successful on volume vol1 of Vserver nfssvm. cluster::> cluster::> run -node jsiva-90-01 vol options vol1 nosnap=off, nosnapdir=off, minra=off, no_atime_update=off, nvfail=off, ignore_inconsistent=off, snapmirrored=off, create_ucode=on, convert_ucode=on, maxdirsize=83804, schedsnapname=create_time, fs_size_fixed=off, guarantee=volume, svo_enable=off, svo_checksum=off, svo_allow_rman=off, svo_reject_errors=off, no_i2p=off, fractional_reserve=100, extent=off, try_first=volume_grow, read_realloc=off, snapshot_clone_dependency=off, dlog_hole_reserve=off, space_slo=none cluster::>

Additionally, this change does not bring back the old behavior but just the naming of the latest snapshot.
This means with ordinal naming enabled, the latest snapshot is always "<prefix>.0" where <prefix> is the snapshot policy prefix (i.e. 5min, hourly, weekly, etc).
When the snapshot policy needs to make another snapshot (a new latest snapshot), the latest snapshot is renamed to a snapshot with a create_time format.

For example, use an hourly snapshot policy with ordinal naming enabled:

Scheduled Snapshot Creation Time	Snapshot List	Creation Timestamp
8:00am	hourly.0	2016-06-23_0800
9:00am	hourly.2016-06-23_0800 hourly.0	2016-06-23_0800 2016-06-23_0900
10:00am	hourly.2016-06-23_0800 hourly.2016-06-23_0900 hourly.0	2016-06-23_0800 2016-06-23_0900 2016-06-23_1000
11:00am	hourly.2016-06-23_0800 hourly.2016-06-23_0900 hourly.2016-06-23_1000 hourly.0	2016-06-23_0800 2016-06-23_0900 2016-06-23_1000 2016-06-23_1100

Example:

Default Behavior:

Check the current snapshot naming scheme:

cluster::> vol show vol1 -fields sched-snap-name vserver volume sched-snap-name ------- ------ --------------- nfssvm vol1 create_time cluster::>

Snap list output displays the snapshots with 'create_time' naming scheme:

cluster::> snap list vol1 ---Blocks--- Vserver Volume Snapshot Size Total% Used% -------- -------- ------------------------------------- -------- ------ ----- nfssvm vol1 hourly.2016-06-23_1309 64KB 0% 13% 5min.2016-06-23_1310 60KB 0% 13% 2 entries were displayed. cluster::>

Change the snapshot naming scheme to ordinal:

cluster::> vol modify vol1 -sched-snap-name ordinal Volume modify successful on volume vol1 of Vserver nfssvm. cluster::>

Verify the changes are applied to the given volume:

cluster::> vol show vol1 -fields sched-snap-name vserver volume sched-snap-name ------- ------ --------------- nfssvm vol1 ordinal cluster::>

Verify the latest snapshot will use the ordinal naming scheme:

When the next snapshot creation occurs per snapshot policy, this new 5min.0 will be renamed back to 'create_time' scheme, while the latest new one will use the ordinal name:

cluster::> snap list vol1

---Blocks---

Vserver Volume Snapshot Size Total% Used% -------- -------- ------------------------------------- -------- ------ ----- nfssvm vol1 hourly.2016-06-23_1309 64KB 0% 12% 5min.2016-06-23_1310 64KB 0% 12% 5min.2016-06-23_1315 64KB 0% 12% 5min.0 60KB 0% 12% 4 entries were displayed. cluster::>

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