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How to resolve issues during storage controller motherboard replacement and head upgrades with iSCSI and FCP

Last Updated:

Applies to

  • SAN
  • FlexPod
  • Data ONTAP 7 and earlier


Storage controller motherboard replacements and head upgrades, when performed improperly can result in loss of the controller’s SAN identity information including Fibre Channel WWN, WWPN and iSCSI IQN. It can also result in existing LUN serial numbers being changed or the loss of LUN to initiator group mappings.
Data ONTAP 7G and Data ONTAP 7-Mode store SAN identity and LUN mapping data in the controller’s root volume. Therefore, the root volume and aggregate must be preserved during a storage controller motherboard replacement or head upgrade.  

LUN serial numbers are automatically changed in the event the aggregate volumes are reassigned from one storage controller to another. The only exception to this is when Data ONTAP determines that a motherboard replacement has occurred. The motherboard replacement detection occurs when all aggregates attached to the storage controller are determined to come from another storage controller. If foreign aggregates are added to a storage controller with existing aggregates and owned disks, then the motherboard replacement detection will fail and any LUNs within FlexVols on the foreign aggregates will receive new serial numbers.

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