[dm-devel] multipath selection based on queue length
Fraser Campbell
fraser at georgetown.wehave.net
Thu Apr 13 20:23:57 UTC 2006
Hi,
Our SAN group would like us to balance I/O requests across all paths
based on queue length. My understanding of this is that we would
essentially route each I/O request down the path with fewest pending I/O
requests (perhaps my understanding is overly simplistic).
Is this possible with dm-multipath, multipath-tools, etc? I am running
SLES 9 which includes dm-multipath 1.0.4 and multipath-tools 0.4.5.
The SAN is a Hitachi Tagma, here is one test LUN:
350060e80000000000000a95200000480
[size=13 GB][features="0"][hwhandler="0"]
\_ round-robin 0 [enabled][best]
\_ 0:0:0:36 sde 8:64 [active]
\_ round-robin 0 [enabled]
\_ 1:0:0:36 sdj 8:144 [active]
That is default config, I have also setup with multibus but our SAN
group does not want us to use round-robin load balancing, nor do they
want us to use single-path I/O as we would get with the failover approach.
Any suggestions?
Thanks,
Fraser
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