288 IBM System Storage N series Hardware GuideSystem and firmware NDU support for stretch MetroClusterMinor and major version NDU is supported in a stretch MetroCluster environment. StretchMetroCluster is essentially an HA pair configuration, so the same limits and qualificationsapply.System and firmware NDU support for fabric MetroClusterMinor version NDU is supported for fabric MetroCluster environments.Major version NDU for fabric MetroCluster is supported from Data ONTAP 7.2.4 (and later) toData ONTAP (7.3.2) and later.20.1.7 System commands compatibilityThe cf takeover -f command cannot be used across minor releases. The download processrequires a clean shutdown of the storage controller for the new kernel image to be installedcorrectly. If the shutdown is not clean, the system reboots with the old kernel image.The cf takeover -n command also cannot be used across minor releases. The cf takeover-n command applies only to major version NDU. It fails if attempted during a minor NDU ornormal takeover.The cf giveback -f command can be used during system NDU. Running this commandmight be necessary when long-running operations or operations that cannot be restarted arerunning on behalf of the partner.20.2 Shelf firmware NDUThe IBM N series disk shelves incorporate controller modules that support firmware upgradesas a means of providing greater stability or functionality. Because of the need foruninterrupted data I/O access by clients, these firmware updates can, depending on themodel of module that is involved, be performed nondisruptively.The N series storage controllers, with integrated SAS disk drives, employ internal SASexpander modules that are analogous to controller modules on stand-alone shelves. At thetime of this writing, these controllers include the N3300, N3600, and N3400 series controllers.
