268 IBM System Storage N series Hardware GuideTable 20-4 shows the maximum number of dense volumes, snapshot copies, LUNs, andvFiler units that are supported for NDU.Table 20-4 Maximum limits for NDU20.1.5 Prerequisites for a system NDUThe following subsections address what needs to be completed before performing a major orminor system NDU.Reading the latest documentationReview the Data ONTAP Upgrade Guide for the version to which you are upgrading, not theversion from which you are upgrading. These documents are available on the IBM Supportsite.Verify that the system and hosts (if applicable) fulfill the requirements for upgrade.Review the release notes for the version of Data ONTAP to which you are upgrading. Releasenotes are available on the IBM Support site.Review the list of any known installation or upgrade problems for both the version of DataONTAP to which you are upgrading, and all host-specific items if your environment uses FCPor iSCSI.Validating the storage controller system configurationsConfirm that both storage controllers are prepared for the NDU operation. Validate eachindividual controller’s configuration to identify any issues before upgrading.Create a detailed upgrade test procedure document and a back-out plan.Identify any inconsistencies between the two storage controllers within the HA pair controllerconfiguration so that all identified issues can be corrected before beginning the upgrade.Removing all failed disksFailed disk drives prevent giveback operations and can introduce stack/loop instabilitythroughout the storage system. Remove or replace all failed disk drives before beginning thesystem NDU operation.When AutoSupport is enabled, failed drives are detected automatically, and replacementdrives are shipped for installation at the administrator's convenience. Generally, enableAutoSupport for all storage systems.Data ONTAP DensevolumesSnapshot copies LUNs vFiler unitsFC, SASstorageSATAstorageFC, SASstorageSATAstorage7.3.x to 8.0 100 500 500 2,000 64 57.3.x to 8.0.1 300 12,000 4,000 2,000 64 57.3.x to 8.1 300 12,000 4,000 2,000 64 58.0 to 8.0.x 300 12,000 4,000 2,000 64 58.0.x to 8.1 500 20,000 20,000 2,000 64 58.1 to 8.1.x 500 20,000 20,000 2,000 64 5
