Bug 49319

Informational

GemStone/S 64 Bit

3.6.1, 3.6, 3.5.7, 3.5.6, 3.5.5, 3.4.5

Configuring Shared Memory on Mac "Big Sur"

On the "Big Sur" release of MacOS (OSx v11.x), the increased security means shared memory configuration, as required for large GemStone installations, has become more restrictive. Setting values in /etc/sysctl.conf is no longer effective. Big Sur is not yet officially supported, but GemStone is expected to run on this platform.

As root, you can manually change the shared memory parameters using /usr/sbin/sysctl; however, changes made in this way are lost on reboot.

To upgrade the configurations permanently, you must set the configuration values in an XML-formatted file with the path and name:
   /Library/LaunchDaemons/com.gemtalksystems.shared-memory.plist

You will need to reboot, for the settings to take effect.

An example plist file for a host with 8 GB of RAM is available at com.gemtalksystems.shared-memory.plist, with the contents below; edit the settings as appropriate for your machine RAM and GemStone configuation.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>shmemsetup</string>
  <key>UserName</key>
  <string>root</string>
  <key>GroupName</key>
  <string>wheel</string>
  <key>ProgramArguments</key>
  <array>
    <string>/usr/sbin/sysctl</string>
    <string>kern.sysv.shmmax=6442450944</string>
    <string>kern.sysv.shmall=1572864</string>
  </array>
  <key>KeepAlive</key>
  <false/>
  <key>RunAtLoad</key>
  <true/>
</dict>
</plist>


Last updated: 4/7/21