OneFS: Sysctl: efs.snapshot.max_snapshots

The cluster may fail to create new snapshots due to the maximum number of snapshots being exceeded. Scheduled Snapshots, SyncIQ, and jobs that create snapshots, such as FSAnalyze or IndexUpdate, may fail. 

One or more messages similar to the following appear in the Event and Message logs.

Failing snap_create. Active snapshot count 20001 exceeds limit of 20000.

Can't create new snapshot <SIQ-Policy>: system-wide snapshot limit has been reached

By default, OneFS allows a maximum of 20,000 snapshots across the entire cluster. The cluster does not allow the creation of additional snapshots until existing snapshots are either manually deleted or expire and deleted by the SnapshotDelete job.

The current number of snapshots on a cluster can be viewed using this command:
 

# isi snap snap list | grep Total

 The maximum snapshots setting can be viewed using this command:

# sysctl efs.snapshot.max_snapshots

The maximum number of snapshots that can be stored across the cluster can be increased. 
 

IMPORTANT!
The ramifications of changing the snapshot limit must be fully understood before applying this sysctl change. Contact Dell Technical Support if there are any questions.

Setting the maximum number of snapshots to a value higher than default may negatively affect cluster performance. If the number of snapshots is unexpectedly exceeding the default limit, a technical issue may be present. Misconfigured Snapshot Schedules, SyncIQ issues, or job failures may be causing the number of snapshots to exceed default limits. Increasing the maximum snapshot limit without addressing these underlying issues can negatively affect the cluster. Technical Support should be contacted to help investigate and resolve these issues if present.

To change the maximum number of snapshots:

# sysctl efs.snapshot.max_snapshots=<#_of_snapshots>

Example: (Increases snapshot limit to 20100)
 

Isilon-2# sysctl efs.snapshot.max_snapshots=20100
efs.snapshot.max_snapshots: 20000 -> 20100

Isilon-2# sysctl efs.snapshot.max_snapshots
efs.snapshot.max_snapshots: 20100

All current versions of OneFS since OneFS 7.1 have a 20000 snapshot limit. Prior versions of OneFS had a 2048 snapshot limit.