Removing and replacing a memory module

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You can remove and replace a faulty dual in-line memory module (DIMM) from a control enclosure. You can also use this procedure to add DIMMs to increase the memory capacity of the node canister.

About this task

Notes:

The memory modules are sensitive to electrostatic-discharge (ESD). Take precautions to avoid damage from static electricity. When you remove or replace this part, you must follow recommended procedures for handling ESD-sensitive devices.
No tools are required to complete this task. Do not remove or loosen any screws when you complete these procedures.

As Figure 1 shows, each node canister contains two processors, which are identified as CPU 0 and CPU 1.

Figure 1. Location of CPUs and DIMM slots

A CPU processor has six memory channels, which are labeled A-F.
Each memory channel has 2 DIMM slots, numbered 0-1. For example, DIMM slots A0 and A1 are in memory channel A.
On the system board, the DIMM slots are labeled according to their memory channel and slot. They are associated with the CPU nearest to their DIMM slots.

You do not have to replace all of the memory modules at the same time. However, when you install memory modules, be sure that you follow the configurations that are described in the following table.

To ensure proper cooling and a steady flow of air from the fan modules in each node canister, blank DIMMs must be inserted in any slot that does not contain a memory module.

Table 1. Available memory configurations for a FlashSystem 7300 control enclosure
DIMM slot	Memory configuration options (per enclosure)
DIMM slot	256 GB	768 GB	1,536 GB
F0	Blank	32 GB	32 GB
F1	Blank	Blank	32 GB
E0	Blank	32 GB	32 GB
E1	Blank	Blank	32 GB
D0	32 GB	32 GB	32 GB
D1	Blank	Blank	32 GB
CPU 1
A1	Blank	Blank	32 GB
A0	32 GB	32 GB	32 GB
B1	Blank	Blank	32 GB
B0	Blank	32 GB	32 GB
C1	Blank	Blank	32 GB
C0	Blank	32 GB	32 GB

C0	Blank	32 GB	32 GB
C1	Blank	Blank	32 GB
B0	Blank	32 GB	32 GB
B1	Blank	Blank	32 GB
A0	32 GB	32 GB	32 GB
A1	Blank	Blank	32 GB
CPU 2
D1	Blank	Blank	32 GB
D0	32 GB	32 GB	32 GB
E1	Blank	Blank	32 GB
E0	Blank	32 GB	32 GB
F1	Blank	Blank	32 GB
F0	Blank	32 GB	32 GB

If a node error 510 is logged (error code 1022 in the system log), the sense data includes the following information, which you can also use to determine which DIMMs need to be replaced.

Detected memory size in MB.
Expected memory size in MB.
A list with one entry per DIMM slot, show the size of the DIMM in GB for each slot.

Procedure

Identifying failed DIMMs

If you are replacing failed DIMMs, use the service assistant or the System Event Log in the management GUI to obtain the sense data. This data shows the detected and expected memory sizes and the size of the DIMM in each slot.
Identify the column in the memory configuration table that contains the expected configuration. To do so, match the expected memory size from the error sense data to the column that has the same node canister total memory.
Compare the size of the DIMM reported in each slot in the error data with the expected DIMM size for the slot index and node canister total memory size that is shown in the memory configuration table. For each mismatch, the DIMM must be replaced with the size of DIMM that is indicated in the table. See the Replaceable units topic in the Reference section for the correct FRU part number for each size of DIMM.

Removing the node canister

Important: Do not start service status on the node. Power off the node to replace a DIMM or run the rmnode command to add DIMMs.

If you are upgrading memory of a node canister as a part of an enclosure upgrade, you must remove that node from the system configuration before you start the following procedure. To do so, you can use the management GUI or the CLI.

To use the management GUI, right-click the node canister and select Remove.
To use the CLI, enter the following command, where object_id | object_name identifies the node canister that receives the additional memory:
```
rmnodecanister object_id | object_name 
```

If you are replacing a faulty DIMM with a new one from FRU stock, you do not need to remove the node canister from the system configuration.

Follow the Procedure - Powering off a node canister to verify that the hosts will not lose access to data in volumes.
Remove the node canister, as described in Reseating a node canister in the control enclosure, and place it on a flat, level surface.

Removing the DIMM

Remove the cover, as described in Removing and replacing the cover of a node canister.
Locate the appropriate DIMM slot.
As Figure 2 shows, the DIMM locations are identified on the system board.
Figure 2. Identifying DIMM locations
Press the locking tabs on the side of the DIMM to eject it.
Lift the DIMM up and out of the slot.
If you have other tasks to complete inside the control enclosure, do those tasks now.

Replacing or adding the DIMM

Important: If you are adding memory to a node canister, you must remove that node from the system configuration before you start the following procedure. To do so, you can use the management GUI or the CLI.

To use the management GUI, right-click the node canister and select Remove.
To use the CLI, enter the following command, where object_id | object_name identifies the node canister that receives the additional memory:
```
rmnodecanister object_id | object_name 
```

If you are replacing a faulty DIMM with a new one from FRU stock, you do not need to remove the node canister from the system configuration.

Touch the static-protective package that contains the new DIMM to any unpainted metal surface on the node canister. Remove the DIMM from the package.
Turn the DIMM so that the DIMM keys align correctly with the connector on the main board.
Insert the DIMM into the connector by aligning the edges of the DIMM with the slots at the ends of the DIMM connector, as shown in Figure 3.

Figure 3. Installing the DIMM

Attention: If there is a gap between the DIMM and the retaining clips, the DIMM is not correctly inserted; open the retaining clips, remove the DIMM, and then reinsert it.
Firmly press the DIMM straight down into the connector by applying pressure on both ends of the DIMM simultaneously. The retaining clips snap into the locked position when the DIMM is firmly seated in the connector.
Repeat steps 11 through 14 until all the new or replacement DIMMs are installed.
Install the cover, as described in Removing and replacing the cover of a node canister.
Reinsert the node canister, as described in Reseating a node canister in the control enclosure.
If the canister does not begin to power up, check that the canister is fully inserted into the enclosure.
When the node is active again, go to the management GUI and look for any unfixed events that are related to the DIMMs.