In these scenarios, multipath processing efficiency is very low:
1) There are many paths in multipath devices,
2) Add/delete devices when iSCSI login/logout or FC link up/down.
Multipath process so slowly that it is not satisfied some applications,
For example,
openstack is often timeout in waiting for the creation of multipath
devices.
The reason of the low processing efficiency I think is that multipath
process uevent
message one by one, and each one also produce a new dm
addition/change/deletion
uevent message to increased system resource consumption, actually most of
these uevent
message have no sense at all.
So, can we find out a way to reduce these uevent messages to promote
multipath
processing efficiency? Personally, I think we can merge these uevent
messages before
processing. For example, during the 4 iSCSI session login procedures, we
can wait for a
moment until the addition uevent messages of 4 paths are all arrived, and
then we can
merge these uevent messages to one and deal with it at once. The way to
deal with
deletion uevent messages is the same.
How do you think about? Any points of view are welcome.
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