Red Hat Bugzilla – Bug 311751
host has 194 LUNs and each LUNs has 15 partitions now. Start with PowerPath also cause the server hang.
Last modified: 2012-06-20 11:55:33 EDT
Description of problem:
In such configuration, during powerpath start, after PP has presented the
native and pseudo devices to the Linux kernel, udev and hotplug systems
trigger thousands events and each of this event spawns a udev and hotplug
process. In this transient system state, the server has more then 5000
hotplug processes and around 3000 udev processes. [ Hotplug and udev
processes present currently available devices to the /dev directory.]. It
takes a long time for these processes to finish, because the partition
events have to wait for the main block device event so the partition event
can import the parents information, already stored in the udev database.
The performance consequences of this to the server can be summarized in a
single word - catastrophe
Version-Release number of selected component (if applicable):
Steps to Reproduce:
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