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Write-cache disabled on storage array causing performance issues or failures

Details

  • Poor disk I/O performance to the storage array, causing very slow or even failure of:
     
    • Template deployments.
       
    • Cold migrations.
       
    • VMotion.
        
    • VCB.
       
  • In the case where the ESX Server environment is large, write caching suddenly becoming disabled can result in a performance degradation makes communication to the LUNs impossible.
     
    • Virtual machines fail or stop responding.
       
    • VMFS datastores go off-line. The error message in the logs is Lost heartbeat .

Solution

Write caching must always be enabled.
 
It is always recommended to have a battery backup connected to ensure that write caching does not become disabled. On many arrays, write caching is automatically be turned off when the battery backup is disconnected, fails, or if one of the redundant power supplies disconnects or fails.

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Actions
  • KB Article: 1002282
  • Updated: Aug 14, 2009
  • Products:
    VMware Consolidated Backup
    VMware ESX
    VMware VirtualCenter
  • Product Versions:
    VMware Consolidated Backup 1.0.x
    VMware ESX 2.0.x
    VMware ESX 2.1.x
    VMware ESX 2.5.x
    VMware ESX 3.0.x
    VMware ESX 3.5.x
    VMware VirtualCenter 2.0.x