Question on routing hotplug events to open-ipmi interface
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?
-Krishna
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Quoted 4 lines · Krishna Pidamale
My system has plenty of hotpluggable SATA drives, and system runs either SLES or RHEL (older and newer distributions). Through
/etc/hotplug/scsi.agentI 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/hotplugutility 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
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THANK YOU Kay for your input, let me dig udevd and more.
-Krishna
Quoted 22 lines · Sievers
Quoted 6 lines · Krishna Pidamale
My system has plenty of hotpluggable SATA drives, and system runs either SLES or RHEL (older and newer distributions). Through
/etc/hotplug/scsi.agentI 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/hotplugutility 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/hotplugis 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/hotplugprocesses, 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.
Quoted 11 lines
There is no way to work with
/sbin/hotplugin 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/hotplugin 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
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Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
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