vSAN Storage Policy Shows Incompatible Due to Zerto IOFilter Watchdog Memory Exhaustion

Products

• VMware vSAN

Issue/Introduction

VMware vCenter UI incorrectly displays a cluster as "Incompatible" when associated with a vSAN Storage Policy containing a Zerto replication component.

* Functional provisioning of Virtual Machines (VMs) remains possible.
* Zerto Virtual Replication Appliances (VRAs) appear healthy in the management console.
* ESXi host logs display the following error: `iofilterd_hpereplication: /bin/watchdog.sh: line 204: can't fork: No space left on device`
* Issue observed on specific hosts  

2026-01-30T04:57:22Z iofilterd_vmwarevmcrypt: ... Start is complete
2026-01-30T04:57:23Z iofilterd_hpereplication: Starting iofilterd and platform VP for hpereplication ...
2026-01-30T04:57:23Z iofilterd_hpereplication: +/bin/watchdog.sh ++group=host/iofilters,mem=8 -d -t 100 -s
iofilterd_hpereplication /usr/lib/vmware/iofilter/bin/iofilterd --filter=hpereplication --mempool=30
/bin/watchdog.sh: line 204: can't fork: No space left on device
2026-01-30T04:57:23Z iofilterd_hpereplication: daemon failed to start, exit status 2

Environment

VMware vCenter Server 8.x +
VMware ESXi Server 8.x +
VMware vSAN Server 8.x+ 
Zerto Virtual Replication  10.80.0.8202-1OEM

Cause

The default memory reservation for the `iofilterd_hpereplication` watchdog process (8 MB) is insufficient on ESXi hosts with high resource utilization. Memory exhaustion prevents the IOFilter daemon from starting, causing the host to fail broadcasting its `hpereplication@replication` capability to the Storage Policy Based Management (SPBM) service during VASA provider queries.

Resolution

1. Contact the third-party vendor (HPE/Zerto) to obtain an updated IOFilter VIB configured with a higher daemon watchdog memory reservation (16 MB).
2. Install the updated IOFilter VIB on all affected ESXi hosts.
3. Restart the IOFilter service on the ESXi hosts by executing the following command:
`/etc/init.d/iofilterd-hpereplication restart`
4. In the vSphere Client, navigate to **Policies and Profiles** > **VM Storage Policies**.
5. Select the affected storage policy.
6. Select **Storage Compatibility** and click **Check Compatibility** to confirm the status updates to "Compatible".