Powershell Incorrect Values for efficiency savings returned

aonsux — Wed, 04 Jun 2025 15:11:25 GMT

I get following output from the cli for one of the volumes I have troubles with:

volume show -vserver swi56saas02b -volume C050_mbrowse_T2M_918_V014 -inst

Vserver Name: swi56saas02b
Volume Name: C050_mbrowse_T2M_918_V014
Aggregate Name: f918xnas001_01_data02
List of Aggregates for FlexGroup Constituents: -
Volume Size: 10TB
Volume Data Set ID: 1073742993
Volume Master Data Set ID: 3221226019
Volume State: online
Volume Style: flex
Extended Volume Style: flexvol
Is Cluster-Mode Volume: true
Is Constituent Volume: false
Export Policy: default
User ID: -
Group ID: -
Security Style: ntfs
UNIX Permissions: ------------
Junction Path: /C050_mbrowse_T2M_918_V014
Junction Path Source: RW_volume
Junction Active: true
Junction Parent Volume: swi56saas02b_root
Comment:
Available Size: 355.1GB
Filesystem Size: 10TB
Total User-Visible Size: 10TB
Used Size: 9.65TB
Used Percentage: 96%
Volume Nearly Full Threshold Percent: 95%
Volume Full Threshold Percent: 98%
Maximum Autosize (for flexvols only): 12.00TB
Minimum Autosize: 10TB
Autosize Grow Threshold Percentage: 95%
Autosize Shrink Threshold Percentage: 50%
Autosize Mode: off
Total Files (for user-visible data): 31876696
Files Used (for user-visible data): 48582
Space Guarantee in Effect: true
Space SLO in Effect: true
Space SLO: none
Space Guarantee Style: none
Fractional Reserve: 0%
Volume Type: RW
Snapshot Directory Access Enabled: true
Space Reserved for Snapshot Copies: 0%
Snapshot Reserve Used: 0%
Snapshot Policy: 30days_Default
Creation Time: Wed Nov 02 21:07:06 2016
Language: en_US
Node name: f918xnas001-01
Clone Parent Vserver Name: -
FlexClone Parent Volume: -
Reserved Space for Overwrites: 0B
Volume Contains Shared or Compressed Data: true
Space Saved by Storage Efficiency: 0B
Percentage Saved by Storage Efficiency: 0%
Space Saved by Deduplication: 0B
Percentage Saved by Deduplication: 0%
Space Shared by Deduplication: 0B
Space Saved by Compression: 0B
Percentage Space Saved by Compression: 0%
Volume Size Used by Snapshot Copies: 81.41GB
Block Type: 64-bit

volume show -vserver swi56saas02b -volume C050_mbrowse_T2M_918_V014 -fields dedupe-space-saved,compression-space-saved
vserver volume dedupe-space-saved compression-space-saved
------------ ------------------------- ------------------ -----------------------
swi56saas02b C050_mbrowse_T2M_918_V014 0B 0B

Here you can see that we don´t have any space savings in this volume. It contains only video files. When we see the same information through powershell they are completely different.

PS C:\Users\Administrator> get-ncefficiency -vserver swi56saas02b -volume  C050_mbrowse_T2M_918_V014


   Vserver: swi56saas02b

Name                       Capacity       Used   SnapshotUsed    Returns  EffectiveUsed  EfficiencyPercent
----                       --------       ----   ------------    -------  -------------  -----------------
C050_mbrowse_T2M_918_...    10,0 TB     9,9 TB       311,4 GB     9,6 TB        19,6 TB             195,7%

We are making internal accounting regarding the values delivered by “EffectiveUsed”. There are only a few volumes were the value is wrong like in the example above.

In my opinion the returns are causing the wrong numbers. The returns in this volume are not 9,6TB!

Any help would be appreciated.

BR Roman

Re: Powershell Incorrect Values for efficiency savings returned

MARC_GALLOWAY — Tue, 18 Apr 2017 11:33:17 GMT

This command should result in what you are seeing above

get-ncvol c050_mbrowse_T2m_918_v014 | Select -expandproperty volumesisattributes

Check out the man page for get-ncefficiency. That cmdlet is used for Netapp's overall efficiency.

The cmdlet returns a VolEfficiencyInfo object for each volume it investigaes. An EfficiencyInfo object contains the following values:
- Capacity: The capacity of the storage object.
- Used: The amount of space used on the storage object.
- Free: The amount of space free on the storage object.
- Returns: A ReturnsInfo object which describes the storage efficiency returns.

The VolEfficiency object returned contains the following volume-specific values:
- SnapshotCount: The number of snapshots of the volume.
- SnapshotReserve: The size of the snapshot reserve for the volume.
- SnapshotUsed: The amount of space used by snapshots.
- SnapshotOverflow: The amount of space consumed by snapshots outside of the snapshot reserve.
- Reserve: The amount of space in the overwrite reserve. This space is saved as overwrite space for LUNs and files that have space reservation
enabled.
- ReserveUsed: The amount of reserve space that is currently in use.
- SpaceReserve: The type of space reservation of the volume. This value can be: none, volume, or file.
- QuotaCommitted: The total amount of space committed on the volume to tree quotas.
- QuotaUsed: The amount of space used on the volume by qtrees with tree quotas set.
- QuotaOvercommit: The amount of space overcommitted to tree quotas. If QuotaCommitted < Capacity then the quota overcommit is zero.
- TotalLunSize: The total sze of all LUNs contained within this volume.
- LunOverprovisionPercent: The LUN over-provisioning percent of the volume. This value is equal to (TotalLunSize / Capacity) * 100.
- EffectiveUsed: The amount of space that would be used without NetApp storage efficiency technologies. This is equal to Used + Returns.
- EfficiencyPercent: A percentage representing the overall storage efficiency of the volume. This is equal to (EffectiveUsed / Capacity) * 100.
- Qtrees: A Hashtable containing the qtrees that exist for the volume."

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Powershell Incorrect Values for efficiency savings returned

Re: Powershell Incorrect Values for efficiency savings returned