VMware has released a critical patch for vSAN 6.0 and 6.5. This patch contains a fix for a highly critical vSAN issue that might cause IO read errors and in some cases severe symptoms such as inaccessible VMs, host failures, or stuck resyncs. The issue manifests itself only under highly specific operations and IO patterns.
The bug only affects All-Flash vSAN configurations with deduplication enabled.
Symptoms for this issues are the following messages in the Events tab:
- "vSAN detected an unrecoverable medium or checksum error for component uuid on disk group uuid."
- "vSAN detected and fixed a medium or checksum error for component uuid on disk group uuid."
The following versions are affected according to KB2151042 and KB2151081.
|ESXi 6.5 Update 1||ESXi650-update1||2017-07-27||5969303|
|ESXi 6.5 Update 1 (Security only)||ESXi650-update1||2017-07-27||5969300|
|ESXi 6.5d (vSAN 6.6 Patch)||ESXi650-201704001||2017-04-18||5310538|
|ESXi 6.5 Express Patch 1a||ESXi650-201703002||2017-03-28||5224529|
|ESXi 6.5 Patch 1||ESXi650-201703001||2017-03-09||5146846|
|ESXi 6.5 Patch 1 (Security Only)||ESXi650-201703001||2017-03-09||5146843|
|ESXi 6.5 GA||2016-11-15||4564106|
|ESXi 6.0 Update 3a (Patch 5)||ESXi600-201706001||2017-06-06||5572656|
|ESXi 6.0 Update 3a (Patch 5) (Security Only)||ESXi600-201706001||2017-06-06||5485776|
|ESXi 6.0 Express Patch 7a||ESXi600-201703001||2017-03-28||5224934|
|ESXi 6.0 Update 3||ESXi600-update3||2017-02-24||5050593|
|ESXi 6.0 Update 3 (Security Only)||ESXi600-update3||2017-02-24||5047589|
|ESXi 6.0 Patch 4||ESXi600-201611001||2016-11-22||4600944|
|ESXi 6.0 Patch 4 (Security Only)||ESXi600-201611001||2016-11-22||4558694|
VMware states that all vSAN customers using All-Flash with deduplication enabled must upgrade to this patch immediately: