Reclaiming Space of Unused LUNs

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Identifying Unmapped (Orphans) LUNs

Over time, as servers connected to a SAN get decommissioned, administrators find an increasing number of unmapped LUNs, or volumes that are no longer used by any server. These LUNs, while unused, still occupy disk space in the filer. Being able to identify such unmapped LUNs and reclaim the disk space uselessly consumed by these LUNs will help administrators avoid unnecessary upgrades and extensions of their filers.

To list the LUNs in a filer that are not mapped to any server and therefore safe to remove, right-click the KM main icon > Reporting > KM Commands > LUNs Mapping Table... Whether a LUN is actually mapped or not is also shown in the infobox of each volume instance.

LUN_Infobox_Mapping

LUN Properties - Infobox tab

To Generate a List for Mapped/Unmapped LUNs

1.In the PATROL Console, click the NetApp Filers icon (to generate a mapping table for all monitored NetApp Filers), or select the specific NetApp Filer for which you need to know LUNs mapping conditions > KM Commands > Reporting > LUNs Mapping Table...
2.Configure the options of the LUNs list.

LUNs_Mapping_Table_Settings

LUNs Mapping Table - Settings

3.Click Show Report to display the list of LUNs according to the options previously set.

LUNs_Mapping_Table_Results

LUNs Mapping Table - Results

Identifying Unused LUNs

When a server is decommissioned or reconfigured, its associated LUNs can stay mapped preventing storage administrator from accurately identifying unused LUNs. Since the KM monitors permanently the traffic on each LUN, it becomes easy to detect LUNs for which the activity is null.

1.Create a PATROL Query in the PATROL Console to show the value of the TimeSinceLastActivity parameter of the SEN_NAP_7|C_LUN class
Open PATROL Central Operator Taskpad.
In the Action menu of the PATROL console, click New Query.

QUERY_Unused_LUNs

PATROL Query – General Tab

2.In the General Tab:
Enter the Query Name (example: Unused LUNs)
Enter the Query Description (optional)
In the Query Results Filter section, select Show Selected Objects and check the Parameters box
In the Additional Filtering section, select the Application Class level filtering and the Enable Parameter level filtering options
3.Open the Application Class tab. In the Pattern Matching section, select Like and type:
SEN_NAP_7_LUN if you are in 7-Mode.
SEN_NAP_C_LUN if you are in C-Mode.

QUERY_Unused_LUNs_Class

PATROL Query – Application Class Tab

4.Open the Parameter tab. In the Pattern Matching section, select Like and type TimeSinceLastActivity

QUERY_Unused_LUNs_Param

PATROL Query – Parameter Tab

5.Click OK to display the results of the query.

QUERY_Unused_LUNs_Results

PATROL Query – Results

noteThe value collected for this parameter upon the first collect reflects the number of days since any activity occurred on the volume for the time observed by the KM, i.e. this first collected metric might not reflect the actual absence of activity on the volume.