Attention: File System Risk Statement; Confirm How You Got To This Power775 Disk Enclosure Rail Service Procedure; Rails Description - IBM Power775 Service Procedure

2.2 ATTENTION: File System Risk Statement

The Global Parallel File System (GPFS) implementation of software RAID stripes data across all the Disk
Enclosures in the cluster. If a single Disk Enclosure is powered off while GPFS is active, the file system will go
into panic and become unavailable.
This service procedure requires powering off a Disk Enclosure and because of this requires interaction with GPFS in
order to limit impact to performance.
2.3 Confirm how you got to this Power775 Disk Enclosure Rail Service
Procedure
You should be performing this procedure if you have determined a Disk Enclosure Rail has failed and needs
replacement.
You should have downloaded this procedure from:
InfoCenter Website: http://publib.boulder.ibm.com/infocenter/powersys/v3r1m5/topic/p7ee2/p7ee2kickoff.htm
This is the only valid source for the latest Power775 Disk Enclosure Rail Service Procedure.
2.4 DE Rails Description
The Power775 Disk Enclosure is supported in the Rack on 2 rail assemblies, one on the left and one on the right of
the Disk Enclosure unit. Figure 1 shows a photograph of the Rail assembly. These Rail assemblies include
integrated SAS cable channels to assist in routing SAS cables from the front of the DE to the back (as shown in
Figure 1 ("D")). Disk Enclosures can be located in up to six positions in the Rack. Figure 2 shows a typical 12-
Node, 1-DE configuration and Figure 3 shows a typical 2-Node, 6-DE configuration.
Power775 Disk Enclosure Rail Service Procedure
Figure 1: DE Rail Assembly Front & Back Views
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