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Re: [dm-devel] Problems with multipathing

Roger Håkansson a écrit :
but it seems assymmetrical.

I guess that you with "asymmetrical" means that paths are only presented
on one controller at a time, more on that later.

Yes, and the "transparent path switching with a penalty" family, which your hardware seems to be part of. Those usually don't need a hardware handler.

Most hardware in this familly need a hardware
handler, and some need the "queue_if_no_path" feature set too.

You'll have to find how your array works and try to figure if some
existing hardware handler does the good thing.

I've done some testing and it seems that multibus works fine, but when a
controller fails and the secondary controller takes over, the
scsi-devices are seen as "dead" and if I, before multipath determines
both paths to be permanently faulty, do a "echo 1 >
/sys/class/scsi_device/1:0:0:0/device/rescan", multipath will not fail
the device.

Do failover device nodes get reassigned during the rescan ?
Like, for example, a configured path sda gets removed and a new path sdb appears ? If so, the FC transport class is in charge of the timeout triggering the dead devices removal.
A hardware handler wouldn't help here.

Can you paste a before/after scsi rescan "multipath -l" output ?


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