Observing high latency issues on VMs on iSCSI based storage on PURE FlashArray

Products

• VMware vSphere ESXi

Issue/Introduction

Virtual Machines running on VMFS storage on PURE storage arrays, using iSCSI, experience high latency. iSCSI connections are also dropping and reconnecting.

This may also be isolated to a single host, which can lead to confusion on if it is an ESXi host side issue or not.

To match this issue, all these signature messages need to be present:

The following logs can be found in /var/run/log on the ESXi host:

Vobd.log shows iSCSI based messages:

vobd[2097814]  [iscsiCorrelator] 3986907780153us: [vob.iscsi.connection.stopped] iScsi connection 0 stopped for vmhba64:C1:T0
vobd[2097814]  [iscsiCorrelator] 3986911055021us: [vob.iscsi.connection.stopped] iScsi connection 0 stopped for vmhba64:C1:T0

Vmkernel.log shows these iSCSI based messages:

vmkwarning: cpu53:2098361)WARNING: iscsi_vmk: iscsivmk_ConnReceiveAtomic:474: vmhba64:CH:1 T:0 CN:0: Failed to receive data: Connection closed by peer

vmkernel: cpu53:2098361)iscsi_vmk: iscsivmk_ConnRxNotifyFailure:1223: vmhba64:CH:1 T:0 CN:0: Connection rx notifying failure: Failed to Receive. State=Online

Syslog.log shows these iSCSI based messages:

Er(27) iscsid[2098421] send_pdu failed rc-22

Wa(28) iscsid[2098421] Kernel reported iSCSI connection 3:0 error (1011) state (3)

Environment

vSphere (all versions)

PURE FlashArray

Cause

This is a rarer iSCSI specific session based problem that has been identified on the storage array side and triggers on a particular set of storage I/O workload patterns.

Resolution

This is a known issue that PURE has identified with their Purity software for their FlashArray systems.

PURE has released a fix in Purity version 6.9.1, released on August 29th, 2025.

Please contact PURE support for further details if needed.