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  1. What limits a Device not to detect multiple LUNs behind a single target? What is required to make this possible in broad perspective?
  2. I want to know if there are any limitations in SAS/SATA or SCSI? (<- My only focus areas)
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What exactly are you after? Do you have a specific problem where a particular implementation is not detecting LUNs? –  the-wabbit Apr 16 '14 at 10:47
    
This question is overly broad, but I sense that you are having a problem detecting more than one LUN on a system you expect to be able to see more. If that's the case, please edit your question to provide more details about the problem. As it is, there is nothing preventing multiple LUN detection except a problem of some sort. –  Basil Apr 16 '14 at 10:48
    
I have SAS controller and I have connected an SAS to SATA inter poser. I'm have connected 2 SATA drives to the inter poser but I'm able to detect only one. How can make it detect both? Is it possible also? –  Tom Iv Apr 19 '14 at 9:53

2 Answers 2

There is no reason a device wouldn't see multiple LUNs behind a target other than a configuration problem or flaky software. There is a limitation in most OSs for how many LUNs they can address, but that's so large that it's not really meaningful. Except on VMWare, apparently.

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It's a fairly normal feature of operating systems to skip any adapters that don't have a LUN 0. I'm also aware that some operating systems may not look for LUNs with high IDs. E.g. Windows won't look for LUNs with IDs > 255. (Or at least, this used to be the case. I haven't bothered checking recently, because my arrays now use per host LUN IDs, rather than per array port)

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