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granularity of load balance
what's the granularity of load balancing? I/O or LUN. in a extreme case, if i have only one LUN, will all I/O to this lun use different path?
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Conor
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September 22nd, 2009 14:00
Conor
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September 22nd, 2009 02:00
PowerPath load balancing in active/active environment works as follows [very rough explanation]:
PowerPath will use the path previously chosen for the I/O against the same device as long as the load on this path is not too high. This explains why, as long as the load generated by the host is not too high, the I/Os are always sent along the same path (giving the impression that PowerPath load-balancing is broken!). [can be seen from powermt display - you will see Q-IO's more on one path than others]
In summary, unless the path that was last used for I/O to that device is very busy, PowerPath will route the I/O along the same path. Otherwise, it will route the I/O down an alternate path (balance the I/Os down alternate path).
Alternately you can chose the round-robin policy where each IO is set down a different path in turn.
SKT2
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September 22nd, 2009 03:00
dingding1
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September 22nd, 2009 08:00
dingding1
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September 22nd, 2009 08:00