Why does the kernel parameter SHMMAX appear to be 0 even after seting it to a higher value on Red Hat Enterprise Linux 32-bit?

Solution Verified - Updated -


  • After setting kernel parameter SHMMAX to a value larger than 4GB on a 32-bit Red Hat Enterprise Linux system, this value appears to be reset to 0.

For example, to check the value of SHMMAX:

# cat /proc/sys/kernel/shmmax
  • This is the default value of SHMMAX.

Then set a new value to SHMMAX, one byte higher:

# echo 4294967296 > /proc/sys/kernel/shmmax
  • Check the value and find that it is 0:
# cat /proc/sys/kernel/shmmax


  • Red Hat Enterprise Linux, all 32-bit versoins

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