From: Farmer, John (john.farmer@tycohealthcare.com)
Date: Sun Jun 13 2004 - 11:09:55 EDT
General architecture:
Host machine with 4 HBA's ---> (two HBA connections each switch)Two
Switches --> M2402 Network Storage Router with one FCP module with two fibre
cables attached (1 fibre from each switch) --> 2 MSL5052 jukeboxes.
A valid result of the above configuration is that each tape drive has four
pathes (albeit they are funnelled down to 2 pathes between the switches and
the M2402) to the tape drives located inside the MSL5052s.
At the O/S level however the first valid path in the hwmgr -show scsi -full
command for each of the tape drives is on bus 3. As a result every backup
that is run sends all the data to the same switch which in turn sends it to
the same FCP port on the M2402. 1 fibre port on the M2402 is fully
utilized and the other is never utilized. As the MSL5052s have an aggregate
of 8 drives I believe I can get a performance increase if I can split the
i/o across the two ports.
Questions:
Can I manually change the first valid path column for each tape drive to
force something a little more like load balancing?
Alternatively,
Is there any automated load balancing that can be turned on to cause it to
round-robin (or some other algorithm) between the various pathes?
The host machine is running 5.1A patch kit 3.
John Farmer, Senior Systems Programmer
Tyco Healthcare/US Surgical
150 Glover Ave
Norwalk, CT 06856
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