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Data Domain - Cannot Recover from NVRAM: Recently Written Data May be Lost

Summary: This article explains how to resolve an issue that causes the Autosupport (ASUP) alert:"Cannot recover from NVRAM: Recently written data may be lost". Symptoms ASUP Alert: Cannot recover from NVRAM: Recently written data may be lost Replication disabled System keeps rebooting System fails to complete boot process Kernel panic ...

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms



Cannot Recover from NVRAM: Recently Written Data May be Lost

PURPOSE

This article explains how to resolve an issue that causes the Autosupport (ASUP) alert: "Cannot recover from NVRAM: Recently written data may be lost".

Symptoms

  • ASUP Alert: Cannot recover from NVRAM: Recently written data may be lost
  • Replication disabled
  • System keeps rebooting
  • System fails to complete boot process
  • Kernel panic

 

APPLIES TO

  • All Data Domain systems
  • All Software Releases

Cause

CAUSE

  • NVRAM not properly transferred during chassis swap
  • NVRAM batteries discharged
  • NVRAM card defective
  • Stale NVRAM contents

Resolution

SOLUTION

This alert is triggered when the NVRAM batteries are discharged causing the data on the NVRAM card to be lost.

If this alert is received after a chassis swap, ensure that the NVRAM card was moved from the old chassis to the new chassis as directed in the FRU document, unless specifically noted otherwise by Data Domain Support.

Battery Charging Procedure

  1. If the system has been offline for a period of time, the NVRAM batteries may have discharged causing this alert. To resolve this condition follow the NVRAM charging procedure 181393 .
  2. If the alert persists, all replication contexts on the source system and any related contexts on the destination systems will need to be broken and reestablished 180668 .

A new NVRAM card is needed if:

  • The NVRAM batteries do not charge completely when following the NVRAM battery charging procedure (Charging NVRAM Batteries 181393 ).
  • The system has been running for more than a week with NVRAM batteries fully charged and one or both of the NVRAM batteries is losing charge.
  • The LEDs indicate a replacement is needed according to the following table:

Table 1: NVRAM LED Behavior

LED Function

Function Description

Action Recommended

DD120/ 4xx/5xx

DD660/ 690g

DD140 / 610/630

DD880/g

Power LED

Green solid:  Input power to NVRAM card is valid

Normal - No action indicated

X

X

X

OFF:  No input power to NVRAM card or on-board FPGA is failing

If other system LEDs are functioning correctly, and/or FAULT LED is solid amber, then replace the card.

 

 

 

Fault LED

Amber blinking: batteries are charging

If the system has been powered off, follow the KB article instructions regarding battery charging.

X

X

X

Amber solid: card has a fault

Replace the NVRAM card

X

X

X

OFF:  batteries are charged and card has no fault

No action needed

X

X

X

Test Button

PUSH this button to test the internal logic and all LEDs  (system must be powered ON for this test)

All 3 LEDs should illuminate when button is pressed. If any LED does not illuminate, the card may be bad - replace it.

X

X

n/a

Remove LED

OFF: Normal.  Should always be OFF except when performing TEST LED function

Not applicable

X

X

n/a

Blue solid: illuminated when TEST LED button is pressed

None

X

X

To replace the NVRAM card, contact your contracted support provider to arrange for a replacement.

NOTE:

For DD880 systems which have two NVRAM cards, follow the procedure to determine which DD880 NVRAM card should be replaced 180740 .

For DD890 systems which have two NVRAM cards, follow the procedure to determine which DD890 NVRAM card should be replaced 181710 .

REFERENCE

  • Charging NVRAM Batteries 181393
  • Replication Resync Explanation 180626
  • Break and Resync Directory Replication 180668

Additional Information

 

 

     

       

        Affected Products

        Data Domain

        Products

        Data Domain
        Article Properties
        Article Number: 000043308
        Article Type: Solution
        Last Modified: 28 Oct 2024
        Version:  3
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