Installing a memory module - IBM BladeCenter HS23

Use these instructions to install memory modules in the blade server.

The blade server has a total of sixteen direct inline memory module (DIMM) slots. The blade server supports very low profile (VLP) DDR3 DIMMs with error code correction (ECC) in 4 GB, 8 GB, and 16 GB capacities. For a list of supported DIMMs for the blade server, see Parts listing.

After you install or remove a DIMM, you must change and save the new configuration information by using the Setup utility. When you turn on the blade server, a message indicates that the memory configuration has changed. Start the Setup utility and select Save Settings (see Setup utility menu for more information) to save changes.

The memory is accessed internally through the system using four channels per microprocessor. Each channel contains two DIMM connectors. The following table lists each channel and which DIMM connectors belong to the channel.

Table 1. Memory channel configuration
Memory channel	DIMM connector (microprocessor 1)	DIMM connector (microprocessor 2)
Channel 0	7 and 8	15 and 16
Channel 1	1 and 2	13 and 14
Channel 2	3 and 4	9 and 10
Channel 3	5 and 6	11 and 12

Depending on the memory mode that is set in the Setup utility, the blade server can support a minimum of 4 GB and a maximum of 128 GB of system memory on the system board in a blade server with one microprocessor. If two microprocessors are installed, the blade server can support a minimum of 8 GB and a maximum of 256 GB of system memory. There are four different memory modes:

Independent channel mode: Independent channel mode gives a maximum of 128 GB of usable memory with one microprocessor installed, and 256 GB of usable memory with two microprocessors installed (using 16 GB DIMMs). The DIMMs can be installed without matching sizes. See the table below for the memory installation order.

Rank sparing mode: In rank sparing mode, one rank of a DIMM in each populated channel is reserved as spare memory. The spare rank is not available as active memory. When the active rank memory fails, its content is copied to the spare rank memory which becomes active. The memory set aside for spare is one rank per channel. The size of a rank varies depending on the DIMMs installed. The DIMM population ordering for rank sparing mode is the same as that for independent channel mode.

Table 2. DIMM population sequence for independent-channel mode and rank-sparing mode
One microprocessor installed	Two microprocessors installed
DIMM connectors 1, 7, 3, 5, 2, 8, 4, and 6	DIMM connectors 1, 16, 7, 14, 3, 9, 5, 11, 2, 15, 8, 13, 4, 10, 6, and 12

Mirrored channel mode: In mirrored channel mode, the memory contents on channel 0 are duplicated in channel 2, and the memory contents of channel 1 are duplicated in channel 3. The effective memory available to the system is only half of that installed. The maximum available memory (with 16 GB DIMMs) is 64 GB for a single microprocessor system and 128 GB for a dual microprocessor system.

Important: The memory configuration of channel 0 must match that of channel 2, and the memory configuration of channel 1 must match that of channel 3. For example, if a 4 GB Dual Rank DIMM is installed into the DIMM connector 3 (channel 0), then a 4 GB Dual Rank DIMM must also be installed into the DIMM connector 7 (channel 2). Memory channel configuration lists each channel and which DIMM connectors belong to the channel.

The following table shows the order that memory DIMMs are installed to use a mirrored channel mode.

Table 3. DIMM population sequence for mirrored channel mode
DIMM pair	DIMM connectors
DIMM pair	One microprocessor installed	Two microprocessors installed
First	1 and 7	1 and 7
Second	3 and 5	14 and 16
Third	2 and 8	3 and 5
Fourth	4 and 6	9 and 11
Fifth	None	2 and 8
Sixth	None	13 and 15
Seventh	None	4 and 6
Eighth	None	10 and 12
Note: The DIMM pairs must be identical in size, type, and rank count.

Attention: DIMMs or DIMM fillers must occupy DIMM connectors 1, 2, 13, 14, 15, and 16 for proper cooling.

To install a DIMM, complete the following steps:

Locate the DIMM connectors (see Blade server connectors). Determine which DIMM connector you will be installing memory into.
If a DIMM filler or another memory module is already installed in the DIMM connector, remove it (see Removing a memory module).
Note: A DIMM or DIMM filler must occupy each DIMM socket before the blade server is turned on.
If you are installing a DIMM in DIMM connector seven through twelve, use your fingers to lift the DIMM access door.
Touch the static-protective package that contains the DIMM to any unpainted metal surface on the BladeCenter unit or any unpainted metal surface on any other grounded rack component in the rack in which you are installing the DIMM for at least two seconds; then, remove the DIMM from its package.
To install the DIMMs, repeat the following steps for each DIMM that you install:
1. Make sure that the retaining clips are in the open position, away from the center of the DIMM connector.
2. Turn the DIMM so that the DIMM keys align correctly with the DIMM connector on the system board.
  Attention: To avoid breaking the retaining clips or damaging the DIMM connectors, handle the clips gently.
3. Press the DIMM into the DIMM connector. The retaining clips will lock the DIMM into the connector.
4. Make sure that the small tabs on the retaining clips are in the notches on the DIMM. If there is a gap between the DIMM and the retaining clips, the DIMM has not been correctly installed. Press the DIMM firmly into the connector, and then press the retaining clips toward the DIMM until the tabs are fully seated. When the DIMM is correctly installed, the retaining clips are parallel to the sides of the DIMM.
If the DIMM access door is open, use your fingers to close it.
Install the cover onto the blade server (see Installing the blade server cover).
Install the blade server into the BladeCenter unit (see Installing the blade server in a BladeCenter unit).