From: Allen Wooden (allen.wooden@harboreast.net)
Date: Wed Mar 15 2006 - 13:40:27 EST
Hi all,
I'm trying to get a understanding on the limits of some FC HBA's.
I've got a V440 that is connected to a EMC CX500 via two (SG-XPCI1FC-QL2) 2Gb single port HBA's (Sun Branded Qlogic cards).
They are in slots 2 and 5 (66Mhz).
I'm using PowerPath for failover and load-balancing.
Would the maximum bus speed be about 503MB/sec? 66000000*8/(1024*1024) = 503MB/sec.
Would it also be correct to say this also comes out to around 4Gbit/sec? 503*8?
Or is that incorrect?
Also, would the line speed of the port be 256MB/sec? ((((1024*1024)*1024)*2)/8)/(1024*1024))
If all the above is true then it appears that I'll saturate the Fibre port long before I saturate the PCI bus. Assuming that is the only thing on that bus.
What is driving this is that I'm doing io tests on the luns using iozone and the average blks/sec transferred
for the time period of the test is equal for each controller. 512bytes per block acording to sar. In this
example the lun is 200GB RAID10. And the average blks/sec transferred per path to the lun 60701/60702 respectively.
So.. using ghetto math..
60701 * 2 = 121402 1k blocks
121402/1024 = 118.55MB/sec
60702 * 2 = 121404 1k blocks
121404/1024 = 118.56MB/sec
I also noticed that when I ran the same test except using forcedirectio mount option,
the time to complete the test doubled (from 5hrs to 10hrs) but the measured transfer rate
only dropped by about 8MB/sec. I would have thought it would have been alot slower.
-- Allen Wooden Harboreast Hosting Solutions http://www.harboreast.net allen.wooden@harboreast.net _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagers
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