Undoing A-SIS Deduplication

1. Stop any running deduplication operations on the volume
   filer> sis stop /vol/vol1
2. Disable A-SIS on the volume:
   filer> sis off /vol/vol1
3. Make the volume “fat” again:
   filer> priv set advanced
   filer*> sis undo /vol/vol1
   filer*> sis status /vol/vol1
   filer*> priv set
   filer>

Enabling & starting Dedup

To Enable dedup on a volume: sis on path

where path is the complete path to the FlexVol volume, ie. /vol/vol1.

To start dedup operations: sis start [-s] [-f] [-d] [-sp] /vol/volname

• The —s option scans the volume completely and you are prompted to confirm if deduplication should be started on the volume.
• The —f option starts deduplication on the volume without any prompts.
• The —d option starts a new deduplication operation after deleting the existing checkpoint information.
• The p option initiates a deduplication operation using the previous checkpoint regardless of how old the checkpoint is. Note: This option should be used along with -s only. This is applicable if checkpoint data is corresponding with the gathering stage.

Creating a dedup schedule

Command: sis config -s schedule path

schedule lists the days and hours of the day that deduplication runs. The schedule can be of the following forms:

• day_list[@hour_list] - If hour_list is not specified, deduplication runs in at midnight on the morning of each scheduled day.
• hour_list[@day_list] - If day_list is not specified, deduplication runs every day at the specified hours.
• A hyphen (-) disables deduplication operations for the specified FlexVol volume.
• auto - Deduplication runs automatically when the number of blocks added or changed since the last deduplication operation (performed either manually or automatically) exceeds approximately 20 percent of the total number of blocks that deduplication has already processed.

path is the complete path to the FlexVol volume.

Example
The following command starts deduplication operations at 11 p.m., Monday through Friday.

• sis config -s mon-fri@23 /vol/vol1

Disabling and undo-ing A-SIS for Netapp R200

Solution

To increase the size of an A-SIS enabled volume beyond the maximum limit for A-SIS, the A-SIS service must be turned off and the changes undone. Undoing A-SIS will re-inflate the file system and could require more disk space than is available in the A-SIS enabled volume. There is no way to expand the volume size until the undo is completed, so the recommended course of action is to create and use a temporary volume and migrate data necessary to free enough space for the re-inflation to complete.

WARNING: Once the volume is grown beyond the maximum size supported for A-SIS, A-SIS will be disabled.

WARNING: Disabling A-SIS will require additional disk space as files will be undeduplicated.

WARNING: Using "sis undo" may require rebaselining of snapmirror or snapvault relationships.

Complete the following steps to undo A-SIS: Note: The undo must be performed from diag mode. The sis undo command can take some time (hours) based on how much data is being un-deduped and the filer type.

• Enter df -s .
  Note the space saved, this is the amount of space that will be necessary for the re-inflation.
• Enter df .
  Note the available space. If it is not greater than or equal to the space saved found in the previous output, space will need to be cleared using other methods to complete the undo--for example, deleting Snapshots or migrating data.
• Enter sis off .
• Enter priv set diag.
• Enter sis undo .

Once the undo is complete, the volume will be a normal FlexVol volume that can be expanded.

Applies to:
All NearStore models
Data ONTAP 7G
A-SIS

Reference: kb35784 from Netapp.