decoding dmidecode memory output on an AIX XE310 compute node

valecs · 04-25-2014, 12:53 PM

I'm helping plan memory upgrades to a server used in a high performance computing cluster. The nodes have model number AIX XE310. The sysadmin does not have records of the current memory configuration and downtime would be a hassle for my colleagues. I'm trying to understand the output of dmidecode to determine the memory configuration, but am confused.

Link to AIX XE310 user's guide

The system surely has a total of 4 GB of memory:

Code:

vale@compute-0-0 ~ % free -m
             total       used       free     shared    buffers     cached
Mem:          3951       2751       1199          0        201        852
-/+ buffers/cache:       1698       2253
Swap:          996         37        959

and I am under the impression that it has 8 slots. However, the output from dmidecode doesn't seem to make that clear. The first section lists "Number Of Devices: 8", which I believe refers to 8 slots. However there are only 4 sections, which follow, and they seem to indicate a total of 2 GB of ram.

I am I missing something?

Code:

[root@compute-0-0 ~]# /usr/sbin/dmidecode -t memory
# dmidecode 2.10
SMBIOS 2.4 present.

Handle 0x0010, DMI type 16, 15 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 64 GB
	Error Information Handle: Not Provided
	Number Of Devices: 8

Handle 0x0011, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0010
	Error Information Handle: No Error
	Total Width: 72 bits
	Data Width: 64 bits
	Size: 1024 MB
	Form Factor: DIMM
	Set: 1
	Locator: DIMM x 2
	Bank Locator: Bank1
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified

Handle 0x0012, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0010
	Error Information Handle: No Error
	Total Width: 72 bits
	Data Width: 64 bits
	Size: 1024 MB
	Form Factor: DIMM
	Set: 1
	Locator: DIMM x 2
	Bank Locator: Bank2
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified

Handle 0x0013, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0010
	Error Information Handle: No Error
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: DIMM
	Set: 1
	Locator: DIMM x 2
	Bank Locator: Bank3
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified

Handle 0x0014, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0010
	Error Information Handle: No Error
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: DIMM
	Set: 1
	Locator: DIMM x 2
	Bank Locator: Bank4
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified

Many thanks,
vale

metaschima · 04-25-2014, 01:36 PM

dmidecode isn't always accurate, but you are very likely to have 8 slots (devices).

2 of the used ones are detected properly, the other 2 are not.

valecs · 04-25-2014, 04:03 PM

OK, fair enough. Does anyone have other suggestions for determining the memory configuration without opening up the chassis? lshw is not installed on the machine and I do not have the ability to install programs. I never directly have root access, but I can request the output of some commands via an email to the sysadmin (a la the output in my first post). (edit: capitalization)