SAS 9.4 WebServer Configuration: apr_shm_create Failed Error and Resolution

Typically post hot fix application, the SAS 9.4 Web Server configuration fails. Reviewing latest error_yyyy_mm_dd_nn.log shows the error as:

[Mon May 04 16:53:44.205145 2026] [slotmem_shm:error] [pid 1234305:tid 1234305] (13)Permission denied: AH02611: create: apr_shm_create(/opt/sas/config/Lev1/Web/WebServer/logs/slotmem-shm-pd6e6e57c_0.shm) failed

Root Cause

In Linux, the shared memory filesystem (/dev/shm) must have the sticky bit and be world-writable for non-root users (like sas) to create the shared memory segments required by the Apache balancer.

The Fix

Check /dev/shm permissions. If the output of ls -ld /dev/shm shows drwxr-xr-x (755) and is owned by root, this is the direct cause of the AH01179: balancer slotmem_create failed error.

You must change the permissions to 1777. This allows any user to create files, but only the owner of a file can delete it (the same way /tmp works).

The command is given below:

sudo chmod 1777 /dev/shm

In our case the value was:

drwxr-xr-x 2 root root         280 Apr 23 18:35 /dev/shm/

It was changed to:

drwxrwxrwt 2 root root 280 May  4 18:10 /dev/shm/

Which fixed the issue and the Web Server started.