4.1 Servicing Memory Risers and DIMMs (CRU)

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Caution - These procedures require that you handle components that are sensitive to static discharge. This sensitivity can cause the component to fail. To avoid damage, ensure that you follow antistatic practices as described in 2.3 Performing Electrostatic Discharge and Static Prevention Measures.

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When replacing or upgrading a DIMM on the server you should consider the following:

• Physical layout of the CPUs, memory risers, and DIMMs

  See 4.1.1 CPUs, Memory Risers, and DIMMs Physical Layout.

• Memory riser population rules

  See 4.1.2 Memory Riser Population Rules.

• Memory riser DIMM population rules

  See 4.1.3 Memory Riser DIMM Population Rules.

• Rules for installing DIMMs across memory risers

  See 4.1.4 Memory Performance Guidelines.

• DIMM rank classifications labels

  See 4.1.6 Supported DIMMs.

• Instructions for installing a DIMM

  See Install Memory Risers and DIMMs.

4.1.1 CPUs, Memory Risers, and DIMMs Physical Layout

The physical layout of the CPUs, memory risers, and DIMMs is shown in CPU and Memory Riser Layout and Memory Riser DIMMs Physical Layout and Population Order.

Figure 4-1 CPU and Memory Riser Layout

4.1.2 Memory Riser Population Rules

The system firmware checks if the installed CPUs are for the Sun Server X2-4. The system firmware raises a fault for memory risers whose model belongs with the other family of CPUs.

The memory riser population rules for the Sun Server X2-4 are as follows:

1. A maximum of two memory risers (numbered MR0 and MR1) are supported per CPU, thus allowing up to eight memory risers in a 4-CPU system, or up to four memory risers in a 2-CPU system.

2. Each memory riser slot in the server chassis must be filled with either a memory riser or filler panel, and each memory riser must be filled with DIMMs and/or DIMM filler panels. For example, in 2-CPU systems, empty CPU sockets (P1 and P3) must have associated memory riser slots populated with two riser filler panels per CPU.

3. Performance-oriented configurations should be configured with two memory risers per CPU. In configurations that do not require two memory risers per CPU, the following guidelines should be followed:

• First populate riser slot MR0 for each CPU, starting with the lowest numbered CPU (P0).

• The populate riser slot MR1 for each CPU, starting with the lowest numbered CPU (P0).

Figure 4-2 Memory Riser DIMMs Physical Layout and Population Order

4.1.3 Memory Riser DIMM Population Rules

The memory riser DIMM population rules for the Sun Server X2-4 are as follows:

1. Maximum memory operating speed is 1066 MHz. This also applies to supported DIMMs rated for higher speeds.

2. Supported DIMMs include single-, dual-, or quad-rank 4 GB, 8 GB, 16 GB and 32 GB JEDEC˘2013standard, DDR3 low voltage ECC RDIMMs.

3. All DIMMs on a CMOD must be the same density and organization.

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   Note - Do not mix dual-rank 16 GB DIMMs with quad-rank 16 GB DIMMs on a CMOD. Mixing DIMMs of different rank or density degrades performance.

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   • Single-rank DIMMs (marked 1Rx8) and dual-rank DIMMs (marked 2Rx4) do not include heat spreaders.

   • Quad-rank DIMMs are marked 4Rx4 and include heat spreaders. DIMMs with heat spreaders have two U-shaped metal clips on the top of the DIMM.

4. Each memory riser supports up to 8 DIMMs, with a maximum 64 DIMMs for a 4-socket Sun Server X2-4.

5. DIMM slots are color coded with the following population order:

   • Blue

   • White

   • Black

   • Green

6. DIMM slots must be populated in matching pairs of identical DIMMs (from the same memory kit) within a processor.

   The recommended DIMM population order, as depicted in Memory Riser DIMMs Physical Layout and Population Order is:

   1. D0/D4

   2. D2/D6

   3. D1/D5

   4. D3/D7

7. Install quad-rank DIMMs before dual-rank DIMMs on the same riser. Specifically, a DRAM channel with both rank types must have the quad-rank DIMM in the D0/D4 or D2/D6 slot.

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   Note - When a mixed quad-rank DIMM and dual or single rank DIMM are on the same memory riser, the quad-rank DIMM should be installed in slot0 of each channel.

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4.1.4 Memory Performance Guidelines

Meeting these guidelines will provide the best system performance. Guidelines are listed in decreasing importance.

1. Provide some DIMMs on every memory riser.

2. Provide DIMMs on every DRAM channel (at least 4 DIMMs per memory riser).

3. For each CPU, have equal total gigabytes on the MR0 and MR1 risers. Memory bandwidth is 5% higher when all pairs of risers have balanced capacity.

4. Spread the memory capacity evenly across the CPUs so the operating system can distribute large memory tasks better.

5. Avoid mixing dual-rank and quad-rank DIMMs in the same memory riser.

4.1.4.1 Recommended Memory Placement

For the Sun Server X2-4, the operating speed of the DIMMs does not decrease as more DIMMs are installed. For best memory performance, follow these simple guidelines to add or replace DIMMs in the server. Use one or more sizes of DIMMs, with an even number of DIMMs of each size.

1. Using the largest-capacity DIMMs, add two DIMMs per riser, starting at P0/MR0, continuing through P3/MR1, and then beginning again at P0/MR0 if necessary, until all of the largest-capacity DIMMs are placed.

   For installations with one DIMM size, all DIMMs will be placed in this step. For installations with additional DIMMs of different sizes, continue to the next guideline step.

   If you are adding or replacing quad-rank (16GB) DIMMs, they can be installed only in D0/D4 slots or D2/D6 slots, or else in DRAM channels where those slots already contain 16GB DIMMs.

2. Using DIMMs of the next largest capacity, add two DIMMs per riser, starting with risers with the fewest DIMMs and proceeding from P0/MR0, continuing through P3/MR1, and then beginning again at P0/MR0 if necessary, until there are no more DIMMs of this size, or all risers have four DIMMs.

   As long as any riser has fewer than four DIMMs, keep repeating this step with the DIMMs of decreasing capacity. When all risers have four DIMMs, continue to the next guideline step.

3. Using DIMMs of the next largest capacity, add two DIMMs per riser to risers with the least total gigabytes. Start from P0/MR0, continuing through P3/MR1, and then begin again at P0/MR0 is necessary.

   Repeat guideline step 3 with all remaining DIMMs, in decreasing order of DIMM capacity, until all DIMMs are placed.

4.1.5 DIMM Fault Isolation

The eight DIMMs supported on each memory riser card in the Sun Server X2-4 are divided into two logical DDR3 channels. The first logical channel contains DIMMs installed in slots D0, D1, D4 and D5. The second logical channel contains DIMMs installed in slots D2, D4, D6 and D7.When one or more DIMMs within a logical DDR3 channel are faulted, all four DIMMs within that logical channel will be disabled by BIOS on subsequent boots. This isolates the faulty component from the system to ensure that proper operation is not compromised by the presence of the faulty component.

4.1.6 Supported DIMMs

Initially supported DIMMs for the Sun Server X2-4 are PC3L-type RDIMMs, which are DDR3 low-voltage DIMMs. Supported DIMM Size and Organization identifies supported DIMM sizes.

Table 4-1 Supported DIMM Size and Organization

4.1.7 Unsupported DIMMs

The Sun Server X2-4 does not support the following DIMMs:

• MetaRAMs

• LR-DIMMs or UDIMM

• DIMMs using 256 Mb or 512 Mb DRAM technologies

• DDR3-800 MHz RDIMMs

• DDR3-978 MHz RDIMMs

4.1.8 Removing and Installing Memory Risers, DIMMs, and Filler Panels

Use the following procedures to remove and install memory risers, DIMMs, and filler panels.

Remove a Memory Riser Filler Panel

1. Prepare for servicing:
   1. Attach an antistatic wrist strap.

      See 2.3 Performing Electrostatic Discharge and Static Prevention Measures.

   2. Power off the server.

      See 2.6 Powering Off the Server.

   3. Extend the server to the maintenance position.

      See 2.4 Positioning the Server for Maintenance.

   4. Remove the top cover.

      See 2.7 Removing the Server Top Cover.

2. Locate the memory riser filler panel you want to remove.
3. Lift the memory riser filler panel straight up to remove it from the memory module socket.

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   Caution - Whenever you remove a memory riser filler panel, replace it with another filler panel or a memory riser; otherwise, the server might overheat due to improper airflow.

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Remove a DIMM Filler Panel

1. Prepare for servicing:
   1. Attach an antistatic wrist strap.

      See 2.3 Performing Electrostatic Discharge and Static Prevention Measures.

   2. Power off the server.

      See 2.6 Powering Off the Server.

   3. Extend the server to the maintenance position.

      See 2.4 Positioning the Server for Maintenance.

   4. Remove the top cover.

      See 2.7 Removing the Server Top Cover.

2. Locate the memory riser containing the DIMM filler panel you want to remove.
3. Lift the memory riser straight up to remove it from the memory module socket.
4. Locate the DIMM filler panel you want to remove.
5. To remove the DIMM filler panel, do the following:
   1. Rotate both DIMM slot ejectors outward as far as they will go.

      The filler panel is partially ejected from the socket.

   2. Carefully lift the DIMM filler panel straight up to remove it from the socket (DIMM Socket Release and Alignment).

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   Caution - Whenever you remove a DIMM filler panel, replace it with another filler panel or a DIMM; otherwise, the server might overheat due to improper airflow.

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Remove a Memory Riser and DIMM

1. Prepare for servicing:
   1. Attach an antistatic wrist strap.

      See 2.3 Performing Electrostatic Discharge and Static Prevention Measures.

   2. Power off the server.

      See 2.6 Powering Off the Server.

   3. Extend the server to the maintenance position.

      See 2.4 Positioning the Server for Maintenance.

   4. Remove the top cover.

      See 2.7 Removing the Server Top Cover.

2. Identify the memory riser with the faulty DIMM by pressing the Fault Remind button on the air divider (Fault Remind Button on the Air Divider).
   • If the memory riser Service Action Required LED is off: all DIMMs on this riser are operating properly.
   • If the memory riser Service Action Required LED is on (amber): one or more of the DIMMs installed on this riser is faulty or misconfigured.

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     Note - Located above the Fault Remind button is the Fault Remind button Power LED. When the Fault Remind button is pressed, the Power LED illuminates (green) to indicate that the remind circuitry is working correctly.

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     Figure 4-3 Fault Remind Button on the Air Divider

     
3. Lift the memory riser that has its Service Action Required LED lit straight up to remove the memory riser from the memory module socket (Removing the Memory Riser).
   

   Figure 4-4 Removing the Memory Riser

   
4. Identify the faulty or misconfigured DIMM(s) by pressing the Fault Remind button on the memory riser (Fault Remind Button on Memory Riser).
   • If the DIMM Service Action Required LED is off: DIMM is operating properly.
   • If the DIMM Service Action Required LED is on (amber): DIMM is faulty or misconfigured and corrective action is required.
     

     Figure 4-5 Fault Remind Button on Memory Riser

     
5. To remove the DIMM do the following (DIMM Socket Release and Alignment):
   1. Rotate both DIMM slot ejectors outward as far as they will go.

      The DIMM is partially ejected from the socket.

   2. Carefully lift the DIMM straight up to remove it from the socket.
      

      Figure 4-6 DIMM Socket Release and Alignment

      

      Figure Legend

      1 DIMM connector slot

      2 DIMM connector key

      3 DIMM ejector lever

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   Caution - Whenever you remove a memory riser or DIMM, you should replace it with another memory riser or a DIMM or a filler panel; otherwise, the server might overheat due to improper airflow.

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   Caution - Be sure to install DIMMs in matched pairs of identical DIMM types (same part number).

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Install Memory Risers and DIMMs

Refer to Installing DIMMs and Installing a Memory Riser Module when completing the following procedure.

1. Unpack the DIMMs and place them on an antistatic mat.
2. Ensure that the ejector levers at both ends of the memory module slot are in a fully open position.
3. Align the DIMM with the empty slot.

   Align the notch in the DIMM with the key in the connector. The notch ensures that the DIMM is oriented correctly.

   
   

   Figure 4-7 Installing DIMMs

   
4. Gently press the DIMM into the slot until the ejector tabs lock the DIMM in place.

   If the DIMM does not easily seat into the connector, verify that the notch in the DIMM is aligned with the key in the connector as shown in DIMM Socket Release and Alignment. If the notch is not aligned, damage to the DIMM might occur.

5. Repeat Step 2 through Step 4 until all replacement DIMMs are installed.
6. Push the memory riser module into the associated CPU memory riser slot until the riser module locks in place.
   

   Figure 4-8 Installing a Memory Riser Module

   
7. Return the server to operation:
   1. Install the top cover.

      See 6.1 Replacing the Server Top Cover.

   2. Return the server to the normal rack position.

      See 6.2 Returning the Server to the Normal Rack Position.

   3. Power on the server.

      See 6.3 Powering On the Server.

Install a Memory Riser Filler Panel

1. Align the memory riser filler panel with the empty slot.
2. Gently press the memory riser filler panel into the slot.
3. Return the server to operation:
   1. Install the top cover.

      See 6.1 Replacing the Server Top Cover.

   2. Return the server to the normal rack position.

      See 6.2 Returning the Server to the Normal Rack Position.

   3. Power on the server.

      See 6.3 Powering On the Server.

Install a DIMM Filler Panel

1. Locate the vacant DIMM slot on the memory riser.
2. Ensure that the ejector levers at both ends of the memory module slot are in a fully open position.
3. Align the DIMM filler panel with the empty slot.
4. Gently press the DIMM filler panel into the slot until the ejector tabs lock the filler panel in place.
5. Return the server to operation:
   1. Install the top cover.

      See 6.1 Replacing the Server Top Cover.

   2. Return the server to the normal rack position.

      See 6.2 Returning the Server to the Normal Rack Position.

   3. Power on the server.

      See 6.3 Powering On the Server.