IT27794: ENABLING CBT WHEN VMWARE SNAPSHOT IS PRESENT CAN CAUSE DATA INTEGRITY ISSUE ON THE TARGET BACKUP VOLUME

APAR status

• Closed as program error.

Error description

• An IBM Spectrum Protect Plus backup may become unrecoverable if
  a VMware snapshot exists on a guest VM and CBT becomes enabled
  during
  the backup. This is a limitation of the VMware VDDK library, if
  snapshots exist on the VMware guest then if CBT tracking becomes
  enabled, then the QueryChangedDiskAreas API might not return any
  
  error or the data returned by QueryChangedDiskAreas might be
  incorrect.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * IBM Spectrum Protect Plus levels  10.1.1 and 10.1.2          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * An IBM Spectrum Protect Plus backup may become unrecoverable *
  * if                                                           *
  * a VMware snapshot exists on a guest VM and CBT becomes       *
  * enabled during                                               *
  * the backup. This is a limitation of the VMware VDDK library, *
  * if                                                           *
  * snapshots exist on the VMware guest then if CBT tracking     *
  * becomes                                                      *
  * enabled, then the QueryChangedDiskAreas API might not return *
  * any                                                          *
  * error or the data returned by QueryChangedDiskAreas might be *
  *                                                              *
  * incorrect.                                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply fixing level when available. This problem is currently *
  * projected to be fixed IBM Spectrum Protect Plus level        *
  * 10.1.2.271 and 10.1.3. Note that this is subject to change   *
  * at the discretion of IBM                                     *
  ****************************************************************
  

Problem conclusion

• Only VMs which had a VMware snapshot and that also had CBT
  disabled prior to the backup being run are impacted by this
  issue
  
  The backup has been updated to detect the existence of VMware
  snapshots before the initial base backup is taken. If a VMware
  snapshot exists and the CBT is disabled then the VM backup will
  fail with error:
  
  Error: Changed block tracking cannot be enabled: one or more
  snapshots present
  
  It is recommended to perform a full base backup of all VMware
  VMs that have user created VMware snapshots
  
  Method 1
  Migrate the VMs from an existing SLA to a new SLA:
  1. Create a new SLA in the "Policy Overview" screen.
  2. Remove each VM from the existing SLA, then assign it to the
  new SLA.
  Note:  New target volumes will be created on the vSnap server,
  leading to increased space utilization. However, space will be
  reclaimed as backups from the old SLA expire. When all
  retentions expire from the old SLA, the old volumes are removed.
  
  
  Method 2
  On the Policy Options on the backup screen, enter a list of VMs,
  
  each separated by a semicolon, on "Force full backup of
  resources"
  Note: This will not create new target volumes. The existing
  VMDKs will be overwritten, which reduces the space requirement.
  
  Method 3
  Open a shell to the the SPP appliance, enter command:
  
  /opt/SPP/tools/scripts/rebaseSLA.sh <SLA Name>
  
  e.g.
  
  /opt/SPP/tools/scripts/rebaseSLA.sh Bronze
  
  This will rebase SLA Bronze
  Are you sure? [y/N]
  
  Enter Y, press return.
  
  Upon successful completion, it will print a summary line
  indicating how many records were modified. e.g.
  WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1
  Successfully reset the SLA
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Modules/Macros

• Hypervis
  

Fix information

• Fixed component name

  SP PLUS

• Fixed component ID

  5737SPLUS

Applicable component levels