Cache disk modules (half-palm NVMe SSDs) provide the cache for the storage system. During the replacement of a cache disk module, you do not need to stop system services.
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.
Figure 1 Slot number of the disk module
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.
- 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 10 seconds after it is removed before you install a new one.
- 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.
- During the replacement of cache disk modules, complete the following operations within three minutes: Pull out the disk drawer, remove and insert cache disk modules, and reset the disk drawer. Otherwise, the heat dissipation of the storage device will be affected and the storage device will be powered off due to high temperature.
- If the replacement is not complete within 3 minutes, reset the disk drawer and wait for at least 10 minutes. After the node temperature returns to normal, open the disk drawer again. If the overtemperature indicator of a node is on, ensure that the disk drawer has been reset and wait until the overtemperature indicator turns off. Wait for 10 minutes until the node temperature returns to normal and open the disk drawer again.Figure 2 Over-temperature alarm indicator
Tools and Materials
- ESD gloves
- ESD wrist strap
- ESD bag
- Labels
Procedure
- Remove the front panel cover.Press the release button on the right of the front panel cover, tilt the front panel cover by 20° to 30° forward, and move the front panel cover rightward to separate it from the groove on the left of the system subrack. Then, remove the front panel cover. See (1), (2), and (3) in Figure 3.
- Pull out the rear disk drawer.
- Before pulling out a disk drawer, ensure that the signal cables connected to the device do not affect the pulling and pushing of the disk drawer.
- Before pulling out a rear disk drawer, raise the handles on the front disk drawer until they are perpendicular to the front disk drawer.
- To prevent the device from being powered off due to high temperature, reset the drawer within 3 minutes after the drawer is pulled out. Slide the drawer back immediately after the overtemperature indicator on the drawer panel turns on.
- If the replacement is not complete within 3 minutes, reset the disk drawer and wait for at least 10 minutes. After the node temperature returns to normal, open the disk drawer again. If the overtemperature indicator of a node is on, ensure that the disk drawer has been reset and wait until the overtemperature indicator turns off. Wait for 10 minutes until the node temperature returns to normal and open the disk drawer again.Figure 4 Over-temperature alarm indicator
Raise the handles on the front disk drawer until the handles are perpendicular to the drawer. Hold the handles on the rear disk drawer and slowly pull out the rear disk drawer. See (1) and (2) in Figure 5. - Remove the faulty cache disk module.
Correctly record the slots where cache disk modules reside.
- Press the release buttons on the protection board of cache disk modules to unlock it and lift the protection board upwards. See (1) and (2) in Figure 6.
- Press the ejector release button on the cache disk module. The ejector lever automatically ejects. See (1) in Figure 7.
- Slowly pull out the cache disk module along the slot. See (2) in Figure 7.
- Put the removed cache disk module into an ESD bag.
- Take the replacement cache disk module out of its ESD bag.
- Install the replacement cache disk module.
Ensure that cache disk modules are inserted into the same slots before and after the replacement. Otherwise, services may be affected.
Raise the ejector lever of the cache disk module completely, push the cache disk module into the slot until it cannot move forward, and then reset the ejector lever. See (1) and (2) in Figure 8. - Check the installation.
After inserting the cache disk module, wait 30 seconds and then check the cache disk module running indicator to determine whether the cache disk module has been successfully installed.
If the cache disk module running indicator is steady green, the cache disk module is successfully installed. In this case, go to 8. Otherwise, the cache disk module fails to be installed and you need to perform the following operations to restore the installation:- Check whether the cache disk module has been firmly inserted. If not, wait one minute and reinsert it.
- If the cache disk module still fails to be installed after you reinsert it, the link of the cache disk slot may be faulty. In this case, contact Huawei technical support.
- Reset the protection board of cache disk modules.Press the protection board of cache disk modules to secure it to the system subrack. See Figure 9.
- Push the rear disk drawer back into the system subrack.Raise the handles on the front disk drawer until the handles are perpendicular to the drawer. Pull the release buttons on both sides of the rear disk drawer upwards, push the rear disk drawer back into the system subrack, and pull down the handles on both front and rear disk drawers to their original positions. See (1), (2), and (3) in Figure 10.
- Install the front panel cover.Align the latch on the left of the front panel cover with the groove on the left of the system subrack, and push the right of the front panel cover. Ensure that the latch on the right of the front panel cover is secured to the system subrack. See (1) and (2) in Figure 11.
Follow-up Procedure
After the cache disk is replaced, label it to facilitate subsequent operations.