Listing the available memory blocks

6.10 LPAR mode z/VM guest

List the available memory to find out how much memory is available and which memory blocks are online.

Procedure

  • Use the lsmem command to list your memory blocks.
    Example:
    # lsmem -a
    Address range                          Size (MB)  State    Removable  Device
    ===============================================================================
    0x0000000000000000-0x000000000fffffff        256  online   no         0
    0x0000000010000000-0x000000001fffffff        256  online   no         1
    0x0000000020000000-0x000000002fffffff        256  online   no         2
    0x0000000030000000-0x000000003fffffff        256  online   yes        3
    0x0000000040000000-0x000000004fffffff        256  online   yes        4
    0x0000000050000000-0x000000005fffffff        256  offline  -          5
    0x0000000060000000-0x000000006fffffff        256  offline  -          6
    0x0000000070000000-0x000000007fffffff        256  offline  -          7
    
    Memory device size  : 256 MB
    Memory block size   : 256 MB
    Total online memory : 1280 MB
    Total offline memory: 786 MB
  • Alternatively, you can list the available memory blocks by listing the contents of /sys/devices/system/memory. Read the state attributes of each memory block to find out whether it is online or offline.
    Example: The following command results in an overview for all available memory blocks.
    # grep -r --include="state" "line" /sys/devices/system/memory/
    /sys/devices/system/memory/memory0/state:online
    /sys/devices/system/memory/memory1/state:online
    /sys/devices/system/memory/memory2/state:online
    /sys/devices/system/memory/memory3/state:online
    /sys/devices/system/memory/memory4/state:online
    /sys/devices/system/memory/memory5/state:offline
    /sys/devices/system/memory/memory6/state:offline
    /sys/devices/system/memory/memory7/state:offline

Note

Online blocks are in use by your Linux® instance. An offline block can be free to be added to your Linux instance but it might also be in use by another Linux instance.