From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kay Sievers Date: Fri, 18 Aug 2006 11:28:14 +0000 Subject: Re: Question on routing hotplug events to open-ipmi interface Message-Id: <1155900494.3333.16.camel@pim.off.vrfy.org> List-Id: References: <44E55918.9000508@sun.com> In-Reply-To: <44E55918.9000508@sun.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Thu, 2006-08-17 at 23:07 -0700, Krishna Pidamale wrote: > My system has plenty of hotpluggable SATA drives, and system runs either SLES or RHEL (older and newer distributions). Through /etc/hotplug/scsi.agent I could verify all hotplug add and remove events with DEVPATH. I would like to pass these event info to OPEN-IPMI interface, which means I will write a small C > program to do this. Can I execute this program from scsi.agent? I am concerned about performance hit due to "n" instances of this executable. Since drives can be added/removed several times, it could add up many events. > > Is this /sbin/hotplug utility meant for such operation? Any suggestions to avoid performance degradation? How can udev help here? Where can I find additional information? Depends on the size of you box. The only sane thing you can do with /sbin/hotplug is to disable it. :) It's simply a fork-bomb that kills your box when you generate a lot of events. Old SLES kernels have kernel code, to limit the number of parallel running /sbin/hotplug processes, standard kernels may create out-of-memory situations on big boxes. Newer udev versions connect with the udevd daemon to the kernel over a netlink socket and don't exec() a binary for every event. Also the created system load created by event handlers is limited by udevd. There is no way to work with /sbin/hotplug in a performance critical setup or on big boxes. Use a newer distro release with a recent kernel +udev, if you expect a lot of events. Everything else may work, but if your setup creates more than the usual number of events you may not even be able to bootup with /sbin/hotplug in use. Thanks, Kay ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid0709&bid&3057&dat1642 _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel