dtmrc · February 13, 2024 18:27 · Jul 20, 2022 · Jul 20, 2022 · Jul 20, 2022 · Jul 20, 2022
diff --git a/README.md b/README.md
@@ -60,3 +60,7 @@ Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking S
 [kernel - How do I increase the max open files in macOS Big Sur? - Super User](https://superuser.com/questions/1634286/how-do-i-increase-the-max-open-files-in-macos-big-sur)
 
 [A launchd Tutorial](https://www.launchd.info/)
+
+[macos - Values from sysctl -A don't match /etc/sysctl.conf even after restart - Unix & Linux Stack Exchange](https://unix.stackexchange.com/questions/689295/values-from-sysctl-a-dont-match-etc-sysctl-conf-even-after-restart/710645)
+
+[macos - "No space left on drive" when trying to allocate more shared memory - Stack Overflow](https://stackoverflow.com/questions/70884304/no-space-left-on-drive-when-trying-to-allocate-more-shared-memory/73058877)
diff --git a/README.md b/README.md
@@ -58,3 +58,5 @@ Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking S
 [c++ - Shared memory "Too many open files" but ipcs doesn't show many allocations - Stack Overflow](https://stackoverflow.com/questions/70988547/shared-memory-too-many-open-files-but-ipcs-doesnt-show-many-allocations)
 
 [kernel - How do I increase the max open files in macOS Big Sur? - Super User](https://superuser.com/questions/1634286/how-do-i-increase-the-max-open-files-in-macos-big-sur)
+
+[A launchd Tutorial](https://www.launchd.info/)
diff --git a/README.md b/README.md
@@ -33,14 +33,22 @@ Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking S
     ```
 * If the `shmmni` or other values didn't change, a reboot is in order
   * Known good output when values are changed successfully
-      ```bash
-      λ tail -f /tmp/sysctl.out
-      kern.sysv.shmmax: 4194304 -> 4194304
-      kern.sysv.shmmin: 1 -> 1
-      kern.sysv.shmmni: 32 -> 4096
-      kern.sysv.shmseg: 8 -> 8
-      kern.sysv.shmall: 1024 -> 1024
-      ```
+    ```
+    λ tail -f /tmp/sysctl.out
+    kern.sysv.shmmax: 4194304 -> 4194304
+    kern.sysv.shmmin: 1 -> 1
+    kern.sysv.shmmni: 32 -> 4096
+    kern.sysv.shmseg: 8 -> 8
+    kern.sysv.shmall: 1024 -> 1024
+    λ sysctl -a | grep shm
+    kern.sysv.shmmax: 4194304
+    kern.sysv.shmmin: 1
+    kern.sysv.shmmni: 4096
+    kern.sysv.shmseg: 8
+    kern.sysv.shmall: 1024
+    security.mac.posixshm_enforce: 1
+    security.mac.sysvshm_enforce: 1
+    ```
 
 ## Sources
 [macos - Values from sysctl -A don't match /etc/sysctl.conf even after restart - Unix & Linux Stack Exchange](https://unix.stackexchange.com/questions/689295/values-from-sysctl-a-dont-match-etc-sysctl-conf-even-after-restart)

diff --git a/README.md b/README.md
@@ -32,6 +32,15 @@ Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking S
     sysctl -a | grep shm
     ```
 * If the `shmmni` or other values didn't change, a reboot is in order
+  * Known good output when values are changed successfully
+      ```bash
+      λ tail -f /tmp/sysctl.out
+      kern.sysv.shmmax: 4194304 -> 4194304
+      kern.sysv.shmmin: 1 -> 1
+      kern.sysv.shmmni: 32 -> 4096
+      kern.sysv.shmseg: 8 -> 8
+      kern.sysv.shmall: 1024 -> 1024
+      ```
 
 ## Sources
 [macos - Values from sysctl -A don't match /etc/sysctl.conf even after restart - Unix & Linux Stack Exchange](https://unix.stackexchange.com/questions/689295/values-from-sysctl-a-dont-match-etc-sysctl-conf-even-after-restart)

diff --git a/README.md b/README.md
@@ -4,7 +4,7 @@ As of at least macOS Catalina 10.15.3, `/etc/sysctl.conf` values are no longer r
 
 Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking SSDs. The fix was to set `shmmni` to `4096`. The following has to happen:
 * [Disable SIP](https://developer.apple.com/documentation/security/disabling_and_enabling_system_integrity_protection)
-  * Disclaimer from Apple
+  * **Disclaimer from Apple**
     > Warning
     > 
     > Disable SIP only temporarily to perform necessary tasks, and reenable it as soon as possible. Failure to reenable SIP when you are done testing leaves your computer vulnerable to malicious code. 
@@ -31,4 +31,13 @@ Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking S
     # recheck sysctl values
     sysctl -a | grep shm
     ```
-* If the `shmmni` or other values didn't change, a reboot is in order
+* If the `shmmni` or other values didn't change, a reboot is in order
+
+## Sources
+[macos - Values from sysctl -A don't match /etc/sysctl.conf even after restart - Unix & Linux Stack Exchange](https://unix.stackexchange.com/questions/689295/values-from-sysctl-a-dont-match-etc-sysctl-conf-even-after-restart)
+
+[Setting shared memory in Catalina | Apple Developer Forums](https://developer.apple.com/forums/thread/669625)
+
+[c++ - Shared memory "Too many open files" but ipcs doesn't show many allocations - Stack Overflow](https://stackoverflow.com/questions/70988547/shared-memory-too-many-open-files-but-ipcs-doesnt-show-many-allocations)
+
+[kernel - How do I increase the max open files in macOS Big Sur? - Super User](https://superuser.com/questions/1634286/how-do-i-increase-the-max-open-files-in-macos-big-sur)
diff --git a/README.md b/README.md
@@ -0,0 +1,34 @@
+# com.startup.sysctl.plist
+
+As of at least macOS Catalina 10.15.3, `/etc/sysctl.conf` values are no longer respected and/or the file straight up doesn't exist (confirmed on macOS Monterey 12.4.)
+
+Ran across a `fio` shm error: `failed to setup shm segment` while benchmarking SSDs. The fix was to set `shmmni` to `4096`. The following has to happen:
+* [Disable SIP](https://developer.apple.com/documentation/security/disabling_and_enabling_system_integrity_protection)
+  * Disclaimer from Apple
+    > Warning
+    > 
+    > Disable SIP only temporarily to perform necessary tasks, and reenable it as soon as possible. Failure to reenable SIP when you are done testing leaves your computer vulnerable to malicious code. 
+* Download `com.startup.sysctl.plist`
+* Move to `/Library/LaunchDaemons/com.startup.sysctl.plist`
+* Load the PLIST after a few housekeeping items
+    ```bash
+    # sanity check
+    sysctl -a | grep shm
+
+    # set permissions
+    sudo chown root:wheel /Library/LaunchDaemons/com.startup.sysctl.plist
+
+    # validate key-value pairs
+    plutil /Library/LaunchDaemons/com.startup.sysctl.plist
+
+    # load plist
+    sudo launchctl bootstrap system /Library/LaunchDaemons/com.startup.sysctl.plist
+
+    # check logs
+    tail -f /tmp/sysctl.out
+    tail -f /tmp/sysctl.err
+
+    # recheck sysctl values
+    sysctl -a | grep shm
+    ```
+* If the `shmmni` or other values didn't change, a reboot is in order
diff --git a/com.startup.sysctl.plist b/com.startup.sysctl.plist
@@ -0,0 +1,27 @@
+<?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">
+<!-- DISABLE SIP TO USE: macOS Recovery > Utilities > Terminal > `csrutil disable` > Reboot -->
+<plist version="1.0">
+    <dict>
+        <key>Label</key>
+        <string>com.startup.sysctl</string>
+        <key>LaunchOnlyOnce</key>
+        <true/>
+        <key>StandardErrorPath</key>
+            <string>/private/tmp/sysctl.err</string>
+        <key>StandardOutPath</key>
+            <string>/private/tmp/sysctl.out</string>
+        <key>ProgramArguments</key>
+        <array>
+            <string>/usr/sbin/sysctl</string>
+            <string>-w</string>
+            <string>kern.sysv.shmmax=4194304</string>
+            <string>kern.sysv.shmmin=1</string>
+            <string>kern.sysv.shmmni=32</string>
+            <string>kern.sysv.shmseg=8</string>
+            <string>kern.sysv.shmall=1024</string>
+        </array>
+        <key>RunAtLoad</key>
+        <true/>
+    </dict>
+</plist>