Virtual Address Space Allocation (Linux)
For optimal performance, X100 by default allocates a large amount of virtual address space to be able to use it most efficiently when needed. In some circumstances, this amount can be larger than the amount of physical memory.
Some Linux distributions by default disallow reserving unlimited virtual address space. We recommend that you configure your system to allow unlimited allocation of virtual address space unless there are compelling reasons (unrelated to X100) not to.
To check if your system allows unlimited allocation of virtual address space:
# cat /proc/sys/vm/overcommit_memory
should return 1.
# ulimit –v
should return unlimited.
To ensure the system does not limit allocation of virtual address space
Issue these commands after every system restart:
# echo 1 > /proc/sys/vm/overcommit_memory
# ulimit –v unlimited
To learn how to make this setting persistent, refer to your Linux documentation.
Alternatively, X100 can be configured to not reserve virtual address space by setting the [memory]
max_overalloc (see
max_overalloc) configuration parameter to 0. This may limit the maximum performance your system can deliver.
Note: If you reconfigure your system after Actian X is installed to allow unlimited allocation of virtual address space, then you must also set the max_overalloc parameter correctly (to 2G by default).
Linux: To use the vwload command in parallel mode, /proc/sys/vm/overcommit_memory must be set to 1 or [memory] max_overalloc must be 0.
Last modified date: 08/14/2024