Dell EMC ME4 Series - Replacing an I;O Module (IOM)

• Figure 51. Removing a DDIC (1 of 2) shows dual-indexing of disk slots across front, middle, and back rows of a drawer.
The 5U84 ships with drawers installed in the chassis. However, to avoid shock and vibration issues during transit, the enclosure does not
ship with DDICs installed in the drawers. An enclosure is congured with either 42 disks (half-populated) or 84 disks (fully populated) for
customer delivery. If half-populated, the rows containing disks should be populated with a full complement of DDICs (no blank slots in the
row). The bullet-list below identies rows in drawers that should contain DDICs when the enclosure is congured as half-populated:
• Top drawer–front row
• Top drawer–middle row
• Bottom drawer–front row
If additional disks are incrementally installed into a half-populated enclosure, the DDICs must be added one complete row at a time (no
blank slots in row) in the sequence listed:
• Bottom drawer–middle row
• Top drawer–back row
• Bottom drawer–back row
Replacing an I/O Module (IOM)
NOTE: Whereas the 2U enclosures support single or dual-IOM conguration, the 5U84 enclosures support dual-controller
conguration only. If a partner controller fails, the storage system will fail over and run on a single controller module until the
redundancy is restored. For 5U84 enclosures, an IOM must be installed in each IOM slot. For 2U enclosures, an IOM must be
installed in IOM-slot A, and either an IOM or IOM-blank must be installed in IOM-slot B to ensure sucient air ow through the
enclosure during operation.
I/O module (IOM) denotes either a controller module or an expansion module. In a dual-controller conguration, controller and expansion
modules are hot-swappable, which means you can replace one module without halting I/O to disk groups, or powering o the enclosure. In
this case, the second module takes over operation of the storage system until you install the new module.
You might need to replace a controller module or an expansion module when:
• The Fault LED is illuminated
• Health status reporting in the ME Storage Managerindicates a problem with the module
• Events in theME Storage Manager indicate a problem with the module
• Troubleshooting indicates a problem with the module
The illustrations show IOM module replacement within the top slot (A) as you view the enclosure rear panel. To replace an IOM in the
bottom slot (B), you would rst rotate the module 180º about its longitudinal axis, so that it properly aligns with its connectors on the back
of the midplane. See Figure 10. 2U controller enclosure—rear panel components (4-port FC/iSCSI).
NOTE
: In dual-controller congurations featuring one healthy partner controller, there is no need to transport failed controller
cache to a replacement controller because the cache is duplicated between the controllers, provided that volume cache is set to
standard on all volumes in the pool owned by the failed controller.
Before you begin
Removing a controller or expansion module from an operational enclosure signicantly changes air ow within the enclosure. Openings
must be populated for the enclosure to cool properly. Leave modules in the enclosure until ready to install a replacement. If replacing both
controllers in a dual-controller enclosure, use the ME Storage Manager to record conguration settings before installing the new controller
modules. See Removing an IOM and Installing an IOM for instructions on installing an additional controller module.
CAUTION
: When replacing a controller module, ensure that less than 10 seconds elapse between inserting it into a slot and fully
latching it in place. Not doing so might cause the controller to fail. If it is not latched within 10 seconds, remove the controller
module from the slot, and repeat the process.
66 Module removal and replacement