VNX: "Lost Access to Volume" and "Performance Deteriorated" messages in vSphere for several ESXi hosts.

Summary: Receiving "Lost access to Volume: " and "Performance Deteriorated" messages in vSphere for several ESXi hosts.

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Symptoms

Issue noticed since implementation of the VNX (for well over a year) with no changes; typically user dealt with the disconnects until they became much more frequent and too bothersome to ignore. 

Receiving constant disconnects, VM hangs, latency issues, and/or the following messages: "Lost access to volume <WWN> due to connectivity issues" or "Performance Deteriorated" in vSphere/ESXi kernel logs.

Cause

Near constant Forced Flushing was noticed to be occurring and causing massive overload on the underlying RAID Group SAS disks in a striped MetaLUN configuration. 

VAAI ATS heartbeat was enabled and being used with ESXi 5.5 Update 2.

Resolution

  1. Correct the Forced Flushing by mirroring the existing MetaLUN configuration (MetaLUNs were striped across 3 RAID Groups (RG)), and re-striping across the newly created RGs. This results in each MetaLUN striped across 6 RGs which completely resolved the Forced Flushing issue. However, the disconnects are still occurring, just at a much less rapid rate. 
  2. After checking with VMware, they provided a KB article https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2113956 which was an exact match to our issue. User was running ESXi 5.5 U2 and receiving the same messages in the Kernel Logs as well as being seen on the individual hosts in vSphere. After disabling VAAI, issue was completely resolved. 

Additional Information

**Network was thoroughly checked over and found to have no issues; no slow drain devices, CRC errors, enc_out's, etc.**

**Issue seemed to not be fully related to storage as user was also seeing this issue on XIO storage system.**

Affected Products

Entry Level & Midrange
Article Properties
Article Number: 000052377
Article Type: Solution
Last Modified: 29 Jul 2025
Version:  4
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