Table19-1 Typesof maintenance for fan unit
Configuration Active/hot Active/cold Inactive/hot Inactive/cold Systemstopped
Building block configuration
Supported Unsupported
(*1)
Supported Unsupported
(*1)
Supported(*2)
*1: Ifany physical partition is currently operating ,the cr ossbar box cannot be powered off.
*2: Allthe physical partitions must be powered off, an dthe s ystem must be completely shut down.
Table19-2 Maintenanceflow
Detailsof update process Replacement
1 Preparation 19.3
2 Removinga fan unit 19.4
3 Installingafanunit 19.5
4 Restoringthe system 19.6

19.2.1 T ypes of maintenance

Table19-1 lists the types of maintenancefor the fan units. For the definition of
maintenance,see "4.3 UnderstandingTypes of Maintenance."

19.2.2 Maintenance flow

Table19-2 lists the sequence of the mai ntenance procedure for the fan units.

19.2.3 P recautions for replacement

Notethe foll owing points when replacing a fan unit:
■When replacing multiple fan units, replace one unit at a time. If a redundant
configuration cannot be assured, perform cold replacement.
■Theco oling fans have a redundant configuration. Thus, the system can continue
operating even if one of the fans in the fan units experiences a failure. Avoid
operating the system with a faulty fan for an extended period and replace the fan
unitco ntaining the failed fan as soon as possible.
19.3 Enabling the Removal of a Fan Unit
Thissectio n describes the preparations that must be completed prior to removing a
Chapter19 Maintainingthe Fan Units of the Crossbar Box 329