5.示例
5.1 查看当前内存和支持的最大内存
Linux下，可以使用free或者查看meminfo来获得当前的物理内存：
# free total used free shared buffers cached Mem: 8182532 8010792 171740 0 148472 4737896 -/+ buffers/cache: 3124424 5058108 Swap: 4192956 3304 4189652 # grep MemTotal /proc/meminfo MemTotal: 8182532 kB
这里显示了当前服务器的物理内存是8GB。
服务器到底能扩展到多大的内存？
#dmidecode -t 16 # dmidecode 2.7 SMBIOS 2.4 present. Handle 0×0013, DMI type 16, 15 bytes. Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: Multi-bit ECC Maximum Capacity: 64 GB （可扩展到64GB） Error Information Handle: Not Provided Number Of Devices: 4
但是，事实不一定如此，因此插槽可能已经插满了。也就是我们还必须查清这里的8G到底是4*2GB, 2*4GB还是其他？
如果是4*2GB，那么尽管可以扩展到64GB，但是插槽已经插满，无法扩展了：
#dmidecode -t 17 # dmidecode 2.7 SMBIOS 2.4 present. Handle 0×0015, DMI type 17, 27 bytes. Memory Device Array Handle: 0×0013 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 2048 MB 【插槽1有1条2GB内存】 Form Factor: DIMM Set: None Locator: DIMM00 Bank Locator: BANK Type: Other Type Detail: Other Speed: 667 MHz (1.5 ns) Manufacturer: Serial Number: BZACSKZ001 Asset Tag: RAM82 Part Number: MT9HTF6472FY-53EA2 Handle 0×0017, DMI type 17, 27 bytes. Memory Device Array Handle: 0×0013 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 2048 MB 【插槽2有1条2GB内存】 Form Factor: DIMM Set: None Locator: DIMM10 Bank Locator: BANK Type: Other Type Detail: Other Speed: 667 MHz (1.5 ns) Manufacturer: Serial Number: BZACSKZ001 Asset Tag: RAM83 Part Number: MT9HTF6472FY-53EA2 Handle 0×0019, DMI type 17, 27 bytes. Memory Device Array Handle: 0×0013 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 2048 MB 【插槽3有1条2GB内存】 Form Factor: DIMM Set: None Locator: DIMM20 Bank Locator: BANK Type: Other Type Detail: Other Speed: 667 MHz (1.5 ns) Manufacturer: Serial Number: BZACSKZ001 Asset Tag: RAM84 Part Number: MT9HTF6472FY-53EA2 Handle 0x001B, DMI type 17, 27 bytes. Memory Device Array Handle: 0×0013 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 2048 MB 【插槽4有1条2GB内存】 Form Factor: DIMM Set: None Locator: DIMM30 Bank Locator: BANK Type: Other Type Detail: Other Speed: 667 MHz (1.5 ns) Manufacturer: Serial Number: BZACSKZ001 Asset Tag: RAM85 Part Number: MT9HTF6472FY-53EA2
根据上面输出可以发现，如果要扩展，只有将上面的内存条换成16GB的，才能达到4*16GB=64GB的最大支持内存。
附录：
dmidecode支持的数字参数：
Type Information 0 BIOS 1 System 2 Base Board 3 Chassis 4 Processor 5 Memory Controller 6 Memory Module 7 Cache 8 Port Connector 9 System Slots 10 On Board Devices 11 OEM Strings 12 System Configuration Options 13 BIOS Language 14 Group Associations 15 System Event Log 16 Physical Memory Array 17 Memory Device 18 32-bit Memory Error 19 Memory Array Mapped Address 20 Memory Device Mapped Address 21 Built-in Pointing Device 22 Portable Battery 23 System Reset 24 Hardware Security 25 System Power Controls 26 Voltage Probe 27 Cooling Device 28 Temperature Probe 29 Electrical Current Probe 30 Out-of-band Remote Access 31 Boot Integrity Services 32 System Boot 33 64-bit Memory Error 34 Management Device 35 Management Device Component 36 Management Device Threshold Data 37 Memory Channel 38 IPMI Device 39 Power Supply
