SnapMirror Sync Pause Causes ~10s IO Hang on A150 but Not on FAS2720 (ONTAP 9.14)

Steven_L — Mon, 16 Mar 2026 08:04:40 GMT

Hello everyone,

I am currently testing SnapMirror synchronous replication using two A150 systems. During testing, I observed that when I click Pause on the SnapMirror relationship, the source volume experiences a short IO hang.

However, when performing the same test using FAS2720 systems, the IO hang does not occur.

Environment details:

Source and destination systems: A150
ONTAP version: 9.14
Replication type: SnapMirror Sync (not StrictSync)
Operation performed: Pause the SnapMirror relationship from the GUI

Observed behavior:

When pausing the relationship on A150, IO on the source volume becomes temporarily unresponsive.
The IO hang lasts for approximately 10+ seconds and then automatically recovers.
When performing the same operation on FAS2720 with the same ONTAP version, IO continues normally and no hang is observed.

I have confirmed that the relationship type is Sync, not StrictSync.

My understanding is that in Sync mode, pausing the relationship should not cause a noticeable IO interruption on the source volume.

Questions:

Is this expected behavior for A150 platforms?
Are there any platform-specific differences between A150 and FAS2720 regarding SnapMirror Sync pause behavior?
Is there any known issue or documentation related to this behavior in ONTAP 9.14?

Any insights or documentation references would be greatly appreciated.

Thank you.

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SnapMirror Sync Pause Causes ~10s IO Hang on A150 but Not on FAS2720 (ONTAP 9.14)