Replacing a Cache Disk Module (2 U/4 U x86 Hardware or 2 U/4 U Kunpeng Hardware)

Impact on the System

• If a cache disk module is faulty, the system performance decreases by 30% to 35% but data consistency is not affected.
• During the replacement of a cache disk module, the system performance will decrease. Therefore, you are advised to replace a cache disk module during off-peak hours.
• During the replacement of a cache disk module, the data durability decreases during data reconstruction. After the reconstruction is complete, the data durability recovers.

Prerequisites

• The replacement disk module (spare part) has been prepared.
• The faulty disk module has been located.

Precautions

• To prevent replacement failures, ensure that the replacement cache disk module is free from obvious foreign objects, collision, and scratches.
• To prevent replacement failures, ensure that the cache disk slot is free from foreign objects or obvious damage before installing the cache disk module.
• A node can remain in maintenance mode for 45 minutes. After that, you need to manually switch the node to the maintenance mode again.
• To prevent system faults, use the BOM code of the faulty disk module to apply for a replacement disk module.
• When replacing a cache disk module, wait 30 seconds after it is removed before you install a new one.
• NVMe SSDs support only orderly hot swap. Before removing an NVMe SSD, stop all services accessing it.
• Remove cache disk modules in sequence. Remove one cache disk module completely before removing another.
• Install cache disk modules in sequence. Install one cache disk module completely before installing another.

Tools and Materials

• ESD gloves
• ESD wrist strap
• ESD bag
• Labels

Procedure

1. Remove the disk module.
   

   When removing disk modules, correctly record the slots where disk modules reside.

   1. Press the ejector release button on the disk module. The ejector lever automatically ejects. See (1) in Figure 1.
      Figure 1 Removing a disk module
      
   2. Hold the ejector lever, and pull out the disk module for approximately 3 cm. See (2) in Figure 1.
   3. Wait at least 30 seconds until the disk stops spinning, and then slowly pull out the disk module. See (3) in Figure 1.

2. Put the removed disk module into an ESD bag.
3. Take the replacement disk module out of its ESD bag.
4. Install the disk module.
   

   Ensure that disk modules are inserted into the same slots before and after the replacement. Otherwise, services may be affected.

   1. Open the ejector lever completely, and push the disk module in along the guide rails until it cannot move forward. See (1) in Figure 2.
      Figure 2 Installing a disk module
      
   2. Ensure that the ejector lever is fastened to the chassis beam, and then close the ejector lever to completely insert the disk module into the chassis. See (2) in Figure 2.

Follow-up Procedure

After the cache disk is replaced, label it to facilitate subsequent operations.