How to replace and install cables in a Cable Management Arm (CMA) in Engineered Systems Racks [VCAP]

Asset ID:	1-71-1444683.1
Update Date:	2017-06-02
Keywords:

Solution Type Technical Instruction Sure

Solution 1444683.1 : How to replace and install cables in a Cable Management Arm (CMA) in Engineered Systems Racks [VCAP]

Applies to:

Exadata Database Machine V2 - Version All Versions and later
Exadata Database Machine X2-2 Hardware - Version All Versions and later
Exadata Database Machine X2-2 Full Rack - Version All Versions and later
Exadata Database Machine X2-2 Half Rack - Version All Versions and later
Exadata Database Machine X2-2 Qtr Rack - Version All Versions and later
Information in this document applies to any platform.

Goal

How to manage cable management arms (CMA's) in servers used in Engineered Systems racks - install, replace, add customer network cables - without breaking them.

Solution

DISPATCH INSTRUCTIONS
WHAT SKILLS DOES THE FIELD ENGINEER/ADMINISTRATOR NEED: Exadata trained
TIME ESTIMATE: 60 minutes
TASK COMPLEXITY: 3

FIELD ENGINEER/ADMINISTRATOR INSTRUCTIONS:
PROBLEM OVERVIEW:

Cable Management Arms (CMAs) used in Engineered Systems racks can be broken if not installed correctly, if the cables in them are not installed correctly, or not handled and managed with care when sliding servers to the maintenance position in front of the rack.

a) All Customer network data cables added to the 1U database nodes need to have enough slack and be routed through the CMAs. Feeding them loose through the space between arms may lead to cable damage, port damage to the connectors on PCI cards and motherboards requiring replacements, and CMA damage when sliding out servers for maintenance.

b) Sliding out servers too fast and without care for how the CMA is traveling correctly within the server's rack space can cause them to catch on each other and damage them, or the cables.

c) Not securing cables properly into the CMA can lead to over tension on the cables which then strains the arm, causing it to break. Ensure any cabling done for upgrades or replacements uses velcro to secure cable bundles at the same points the factory cabling does on systems not being upgraded.

Damaged CMA parts usually cannot be fixed and should be replaced with a new one.

WHAT STATE SHOULD THE SYSTEM BE IN TO BE READY TO PERFORM THE
RESOLUTION ACTIVITY?:

It will depend on the reason for the service whether the server will be up and running or be shutdown prior, for which the server and therefore the CMA is being extended to the front of the rack.

WHAT ACTION DOES THE FIELD ENGINEER/ADMINISTRATOR NEED TO TAKE:

Review the attached training videos before performing a CMA replacement and before adding cables into a CMA.

Note there are 2 generations of CMA in use. The older generation use squarish green cable routing clips and only attach in one place on the left side (when looking from rear), and only attaches to the server inner rail on the right side (when looking from rear). The newer generation use a more curved arched grey routing channel clips, with a straight portion across the rear of the server that attaches on the left and right side server inner rail, and pre-installed green velcro attachment loops on the open areas. The older generation will work on server rails used in X3-2/X3-2L and earlier. The newer generation are not supported on systems based on X4170M2 or X4270M2 or earlier; they are only supported on server rails used on X3-2/X3-2L and later.

To Replace a Broken CMA:

1. Lower the Rack stabilization feet on the front of the rack.

2. To gain additional hand and working access space in the rear, slowly slide out the servers immediately above and below the system with the broken CMA, sliding them into the fully extended maintenance position. If the system is at one of the extreme positions of the configuration next to an InfiniBand Switch, then slowly slide out the 2 systems either above or below the system being repaired. Sliding the servers too fast is liable to break these CMA's as well.

3. At the rear of the system being serviced, disconnect all cables at the rear IO panel, carefully noting (via labels or notes) which cable plugs into which connector. On Exadata these are all pre-labelled, except for Database Servers with added customer network cables which should be noted. Review the attached video for more details on installing customer network cables into the CMAs.

4. Remove all cables from damaged CMA by first disconnecting all plastic cable retention clips and and velcro-type cable retainers and then pulling out the cables as a bundles. It might be useful to use velcro cable ties to hold the bundle together to make reinstallation easier.

5. Remove the CMA per the Removal video attached to this note.

6. Set the correct cable clip locations:

On V2, X2-2, X2-8, some X3-2 and some X3-8 systems with the older generation CMA - Relocate the CMA cable clips for Exadata use. CMA FRUs are shipped with the clips in locations that cannot work for Exadata supporting the KVM dongle and IB cables, so they must be removed and relocated when replaced in an Exadata. A flat blade screwdriver can be used to press in the latch and pop the clip off to relocate. Take care to not press too hard or the holding latch will snap and the clip will no longer stay on. 1U and 2U clip location diagrams are attached to this Note. If unsure on the locations, use another server's cabling as reference.
On X3-2/X3-2L and later with the newer generation CMA - The default clip is the flatter 1U clip and should not require to be changed. The rounded 2U clip that comes with the CMA kit may be used on Sparc SuperCluster DB nodes, but otherwise should not be used.

7. Install the new CMA to the rack rails. An Installation video attached to this note covers the older generation CMA. The newer generation CMA attaches in a similar manner, however has an extra attachment point on the left side (when looking from the rear) for the straight bar that attaches to the server inner rail.

8. Open all of the plastic clips on the CMA and loosely dress the cable bundle into the clips. On newer generation CMA's open all of the pre-installed green velcro attachment loops. Get the bundle roughly into position and then make all the appropriate connections to the rear of the system.

9. Starting at the connector end of each cable, dress them into the CMA allowing for some slack so that when the system is fully extended out the front of the rack, they won't be pulled taut. However, don't allow so much slack that the cables droop down or poke up out of the rack unit space reserved for this system. On systems with white cable clips on the rear, the power cables and network cables should be routed through these.

10. Fasten the cable bundle into the CMA using the velcro wraps originally used at the same location points. If unsure on the locations, use another server's cabling as reference.

11. Check to make sure all of the cables have been dressed properly into the CMA, then snap closed all of the plastic clips on the CMA. On 2U Storage Servers, ensure the Infiniband cables are routed above the green clip on the far left, do not route it around the bend in the arm inside the clip, or it may break the cable. If unsure, use another server's cabling as reference.

12. Return to the front of the rack and return the pulled out systems adjacent to the system being repaired, sliding them in slowly to ensure they also do not catch.

13. Fold the Rack stabilization feet back into the rack frame.

OBTAIN CUSTOMER ACCEPTANCE
WHAT ACTION DOES THE FIELD ENGINEER/ADMINISTRATOR NEED TO TAKE TO
RETURN THE SYSTEM TO AN OPERATIONAL STATE:

1. Slowly extract the system being repaired from the rack to check for adequate cable slack and to make sure the CMA has no binding, is free of obstruction, cable tension and interference with other systems. Monitor progress of the cables and CMA as the server comes out. Sliding the server too fast is liable to break the CMA again.
2. If the system fully extends, slide in and out the server one or 2 times to make sure everything has been properly dressed and assembled.
3. Return to rear of rack to make sure all cables and the CMA look good.

PARTS NOTE:

Older Generation - X3-2/X3-2L and earlier systems:

350-1287 - CMA used on 2U Storage Servers
350-1546 - CMA used on 1U Database Servers
350-1502 - Rail kit used on 2U Storage Servers (screw-in)
371-4919 - Long Rail kit used on 1U Database Servers (screw-in)

Note: The CMA extender brackets (350-1514) for the shorter 371-2741 1U Rail kits used on Exadata V2 x4170 dB nodes are not available as FRU's. If the CMA or Rail kit requires replacement on these, then also replace the short rails and extenders with the long rail kit FRU 371-4919.

Newer Generation - X3-2/X3-2L and later systems:

7042273 - 1U/2U Cable Management Arm (Snap-in)
350-1719 - 1U/2U Snap-In Slide Rail Rackmount Kit

Note - on X3-2/X3-2L some systems shipped with older generation CMA's. If broken, it is preferred to replace with the newer generation CMA's, which will also require a replacement of rack rails from screw-in type to snap-in type.

REFERENCE INFORMATION:
The following videos are available in MP4 format for reference how-to's of the physical procedures required by the PM process. These require an MP4 player browser plug-in, such as Apple Quicktime or Real Player, and are attached to this note when viewed in Internal My Oracle Support (MOS/ISP).

Training video for - CMA Removal (3:07)

Training video for - Installing a replacement CMA (2:33) including installing customer data cables.

Training video for - Identifying and Preventing CMA Issues (5:05) that may lead to CMA breakage.

Photo of where green cable support clips should be placed for Exadata (older Generation) - 1U CMA attachment
Photo of where green cable support clips should be placed for Exadata (older Generation) - 2U CMA

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