doc: remove recommendation for kernel.pid_max

now that Ceph uses async messenger, setting kernel.pid_max = 4194303 should not be necessary anymore.  Even if kernel thread limit is 32K and we have 100 drives, that's 320 threads per OSD, I think that should be enough.

Signed-off-by: Ben England <bengland@redhat.com>

diff --git a/doc/start/hardware-recommendations.rst b/doc/start/hardware-recommendations.rst
index 30e00a892461a10f82a80fd2d8a1dda41d943b38..a3277b90f132aef3eb0cd34d31c195375371fce5 100644 (file)
--- a/doc/start/hardware-recommendations.rst
+++ b/doc/start/hardware-recommendations.rst
@@ -205,16 +205,6 @@ is up to date. See `OS Recommendations`_ for notes on ``glibc`` and
 ``syncfs(2)`` to ensure that your hardware performs as expected when running
 multiple OSDs per host.
 
-Hosts with high numbers of OSDs (e.g., > 20) may spawn a lot of threads, 
-especially during recovery and rebalancing. Many Linux kernels default to 
-a relatively small maximum number of threads (e.g., 32k). If you encounter
-problems starting up OSDs on hosts with a high number of OSDs, consider
-setting ``kernel.pid_max`` to a higher number of threads. The theoretical
-maximum is 4,194,303 threads. For example, you could add the following to
-the ``/etc/sysctl.conf`` file:: 
-
-       kernel.pid_max = 4194303
-
 
 Networks
 ========