# How can I view the bandwidth there is available for my disks?



## cedivad (Apr 10, 2012)

I'm hitting a bottleneck, at around 600MB/s, 5k IOPS (read). I would have never imagined to reach such a level, however *I* got there! :stud

The bottleneck must be the connection MB <=> CHASSIS. (the disk subsystem is 40*SSDs, so it's not there )

I have a 9211-8i card, that has a 12Gbps total troughput, however *I* can't understand how can *I* check how it has been configured. I tried running its own utility, but it says that there is no device connected!


```
./sas2ircu LIST
LSI Corporation SAS2 IR Configuration Utility.
Version 13.00.00.00 (2012.02.17) 
Copyright (c) 2009-2012 LSI Corporation. All rights reserved. 

SAS2IRCU: No Controllers Found.
```

Do you know how can *I* see the actual bandwidth among the card and the chassis?

Many thanks forum.


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## Sebulon (Apr 10, 2012)

@cedivad

First off, congratulations!

Well, most SAS controllers have two 600MB/s SAS ports. But your backplane only has one, maxing you out at exactly where you are; 600MB/s. Since thereÂ´s only one SAS port on your backplane, thatÂ´s where your bottleneck is.

If you instead had two backplanes; one for each SAS channel on your HBA, you would get 1,2GB/s.

/Sebulon


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## cedivad (Apr 10, 2012)

Thanks! 

I do have 2 backplanes, *I*'ve yet to understand if they both support 2*6Gbps each (so *I* will end up with 24Gbps) or if they are limited to 1*6Gbps each, so that *I* will end up with 12Gbps. I've asked my system vendor, let*'*s see what he replies =)

(*I* downloaded the pdf manual for the SC417E26-R1400LP, but the file is full of super vectors images that takes a life to load, so *I* gave up )


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## Sebulon (Apr 11, 2012)

@cedivad

Or perhaps more likely is that the backplane has two SAS ports, for failover. That makes it possible to pull out one cable from HBA or backplane without interrupting IO, however that does nothing about raising total throughput. In short, 2xSAS-Failover=600MB/s.

/Sebulon


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