ZFS Snapshot May Leak During a NDMP Backup

Asset ID:	1-77-1444984.1
Update Date:	2012-07-30
Keywords:

Solution Type Sun Alert Sure

Solution 1444984.1 : ZFS Snapshot May Leak During a NDMP Backup

Applies to:

Sun Storage 7110 Unified Storage System - Version Not Applicable to Not Applicable [Release N/A]
Sun ZFS Storage 7120 - Version Not Applicable to Not Applicable [Release N/A]
Sun Storage 7210 Unified Storage System - Version Not Applicable to Not Applicable [Release N/A]
Sun Storage 7310 Unified Storage System - Version Not Applicable to Not Applicable [Release N/A]
Sun ZFS Storage 7320 - Version Not Applicable to Not Applicable [Release N/A]
Information in this document applies to any platform.
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Date of Resolved Release: 29-Mar-2012
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Description

ZFS snapshots, which are temporarily created by Network Data Management Protocol (NDMP) during backup, are not deleted after the backup is done if there are multiple NDMP backup sessions running concurrently. These leaked snapshots may consume excessive disk space and become unmanageable.

Occurrence

This issue can occur in the following releases:

Sun ZFS Storage Appliance Software 2010.Q3.4.2 and earlier releases

Note 1: This issue applies to all Sun ZFS Storage Appliance platforms:

Sun ZFS Storage Appliance 7110, 7120, 7210, 7310, 7410, 7320, 7420

Note 2: To determine the software release on Appliance systems, do the following from the Browser User Interface (BUI) to access "info" about the release name:

Navigate to: Maintenance => System
Click on the "i" next to the "Current System Software" entry in the table of available releases.

A pop-up will show the release. For example: "2010.Q3.3.1"

Symptoms

If the described issue occurs, leaked snapshots will consume disk space and may become unmanageable. To determine if this issue has occurred, do the following:

1. In the Storage Appliance shell select "shares" and the project of interest.

For example:

    7000:> shares select dataproj

2. Observe disk space consumed by snapshots by displaying the value of the "space_snapshots" property.

For example:

    7000:shares dataproj> get space_snapshots
    space_snapshots = 58G

3. Compare this value with the snapshots displayed using the snapshots list command and the "space_data" property for each snapshot.

For example:

    7000:shares dataproj> snapshots list
    snap-20101103

    7000:shares dataproj> snapshots select snap-20101103 get space_data
    space_data = 5G

If the "space_snapshots" property is non-zero and there are no snapshots present or the listed snapshots "space_data" properties don't add up to the "space_snapshots" property total, then this issue is present on the system.

Workaround

To avoid snapshot leaks, run only one backup session at a time.

This issue is addressed in the following release:

For all Sun Storage 7000 Series Unified Storage Systems

Sun ZFS Storage Appliance Software 2011.1.1.0 and later

For a listing of ZFS Storage Appliance Sofware Releases and version information, please see:

https://wikis.oracle.com/display/FishWorks/Software+Updates

History

29-Mar-2012: Date of Resolved Release
30-Jul-2012: Maintenance check for relevance/currency, no change in content

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