Data Domain: Faulty PERC Battery causes degraded performance

Summary: The DD3300 and DP4400 platforms use a PERC H730P Mini RAID controller with a battery-backed cache. If the battery becomes degraded or fails, the controller automatically switches its write policy from Write-Back to Write-Through, resulting in reduced system performance. ...

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Symptoms

Applies to:

  • DD3300
  • DP4400 (IDPA)
  • Dell PowerEdge R740XD with PERC H730P Mini RAID Controller
  • All DDOS Versions

Symptoms:

  • Noticeable drop in system performance
  • iDRAC logs report one or more of the following alerts:
    • "Write policy on Integrated RAID Controller 1 was changed to Write Through"
    • "Virtual Disk 0 write policy has changed"
    • "PERC battery is low"
    • "Battery on Integrated RAID Controller 1 is Degraded or Failed"

    Example iDRAC Log Locations:

    • Storage > Summary > Recently Logged Storage Events
    • Dashboard > Health Information | Recent Logs
    • Storage > Controllers > Controller Battery
      • As captured in the images below:
    1. Storage > Summary > Recently Logged Storage Events
      The image shows an example of Recently Logged Storage Events 
       
    2. iDRAC: Dashboard > Health Information | Recent Logs

    The image shows Health Information and Recent Logs 
     

    1. iDRAC: Storage > Controllers > Controller Battery 


    The image shows Controller Battery status 

     

    Cause

    The PERC H730P Mini controller relies on a battery-backed cache to safely support the Write-Back policy. When the battery is degraded or faulty:

    • The controller switches to Write-Through mode to protect data integrity.
    • This change impacts write performance.
      • Write-Back (WB): Writes complete once data is cached; faster but riskier without battery backup
      • Write-Through (WT): Writes complete only after data is written to disk; safer but slower

    Resolution

    To restore optimal performance:

    1. Confirm the issue by reviewing iDRAC logs and verifying battery status.
    2. Review battery behavior during the Learn Cycle:
      • If the battery cannot hold a 24-hour charge, a "Predicted failure" alert appears. This indicates that the battery is nearing the end-of-life and should be replaced.
      • A "Battery failed" alert during the learn cycle is normal and can be safely ignored. The battery should return to a healthy state within minutes.
      • A "Battery failed" alert outside the learn cycle indicates that the battery has failed and requires immediate replacement.
      • Before replacing, verify that the battery is securely connected to the PERC controller.
    3. Request a replacement PERC H730P Mini card (includes integrated battery).
    4. Contact your Technical Support Provider to initiate a hardware replacement.

    Affected Products

    Data Domain

    Products

    Data Domain, DD3300 Appliance, Data Domain Deduplication Storage Systems, PowerProtect DP4400, Integrated Data Protection Appliance Family, PowerProtect Data Protection Hardware
    Article Properties
    Article Number: 000038067
    Article Type: Solution
    Last Modified: 06 Oct 2025
    Version:  4
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