Lenovo DM120S, Installation And Cabling Manual, Page: 13 / 70

Chapter 2. Hot-adding disk shelves with IOM12 modules
You can hot-add one or more disk shelves with IOM12 modules to an existing stack of disk shelves with
IOM12 modules or hot-add a stack of one or more disk shelves with IOM12 modules directly to a SAS HBA
or an onboard SAS port on the controller.
Requirements for hot-adding disk shelves with IOM12 modules
Your system must meet certain requirements before hot-adding disk shelves with IOM12 modules.
State of your system
• Your system and version of ONTAP must support the disk shelves you are hot-adding, including the IOMs,
disk drives, and SAS cables.
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• Your system must have less than the maximum number of disk drives supported, by at least the number
of disk shelves you plan to hot-add.
You cannot have exceeded the maximum number of disk drives supported for your system after hot-
adding disk shelves.
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• If you are hot-adding a stack of one or more disk shelves directly to a platform controller, each controller
must have enough available PCI SAS HBA or onboard SAS ports or a combination of both.
If you are using SAS HBAs, best practice is to use 12Gb SAS HBAs to keep controller-to-stack
connectivity at 12Gbs for maximum performance.
• Your system cannot have any SAS cabling error messages. You must correct any cabling errors using the
corrective actions provided by the error messages.
Considerations for hot-adding disk shelves with IOM12 modules
You should familiarize yourself with aspects and best practices about this procedure before hot-adding disk
shelves.
General considerations
• If you are hot-adding a disk shelf with IOM12 modules to an existing stack (of disk shelves with IOM12
modules), you can hot-add the disk shelf to either end, the logical first or last disk shelf, of the stack.
• A system can have multipathed and quad-pathed stacks of disk shelves with IOM12 modules. If you have
an HA pair, ONTAP shows the system configuration as “multipath HA”. If you have a single-controller
configuration, ONTAP shows the system configuration as “multipath”.
• This procedure assumes your configuration is using in-band ACP. For configurations that have in-band
ACP enabled, in-band ACP is automatically enabled on hot-added disk shelves. For configurations in
which in-band ACP is not enabled, hot-added disk shelves operate without any ACP functionality.
• Nondisruptive stack consolidation is not supported.You cannot use this procedure to hot-add disk
shelves that were hot-removed from another stack in the same system when the system is powered on
and serving data (I/O is in progress).
Best practice considerations
• The best practice is to have the current version of the Disk Qualification Package (DQP) installed before
hot-adding a disk shelf. Having the current version of the DQP installed allows your system to recognize
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