Hello...

I searched though the mailing list archives and didn't see any mention
of this. I have a rhel 5.1 x86_64 server connected to a NetApp via two
qlogic HBAs (1). I can get 300-350MBytes/sec using a single controller.
However when I configure multipath (3) and use two FC connections ( one
from each FC card), I do not see twice the performance (3), but the same
performance as with a single card. I believe I have multibus enabled
(4).

Should I see twice the performance? Or are two FC cards only good for
failover?

thanks




(*1)
qla2xxx 0000:0f:00.0:
QLogic Fibre Channel HBA Driver: 8.01.07-k7
QLogic QLE2462 - PCI-Express to 4Gb FC, Dual Channel
ISP2432: PCIe (2.5Gb/s x4) @ 0000:0f:00.0 hdma+, host#=1, fw=4.00.150
[IP]


(2)
/etc/multipath.conf:
device {
         vendor            "NETAPP"
         product           "LUN"
         getuid_callout       "/sbin/scsi_id -g -u -s /block/%
n"
         prio_callout        "/sbin/mpath_prio_netapp /dev/%n"
          no_path_retry       fail
         hardware_handler     "0"
         path_grouping_policy   multibus
         failback           immediate
         rr_weight          uniform
         rr_min_io          128
         path_checker        readsector0
         selector           "round-robin 0"
    }


(3)
$ iostat -m 2 # while running iozone
sdd        4068.84      0.00     184.48       0     367
sdf        3952.26      0.00     184.14       0     366
dm-1       94526.13      0.00     369.24       0     734


(4)
~]$ sudo multipath -ll
mpath2 (360a98000486e57735634466a70494859) dm-1 NETAPP,LUN
[size=150G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=8][active]
\_ 1:0:0:1 sdd 8:48 [active][ready]
\_ 3:0:0:1 sdf 8:80 [active][ready]
mpath1 (360a98000486e577356344669746f5841) dm-0 NETAPP,LUN
[size=100G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=8][active]
\_ 1:0:0:0 sdc 8:32 [active][ready]
\_ 3:0:0:0 sde 8:64 [active][ready]


--
Christopher McCrory
"The guy that keeps the servers running"

To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.

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