path of a disk IO

[annie]

Hi all,

I know this is a pretty big question but just trying to learn as much as I can about this topic.

I wanted to understand how IO travels in a SAN. Lets say for example, I have a linux host connected to a SAN.

If I copy a 2MB file, can someone walk me through what happens. I realize a LOT happens but looking for any info you can provide (which will probably lead to me having more questions to look up).

I'm looking for the path from host, to cache, to HBA card, over the fiber channel, to the SAN HBA, disk cache, and onto disk. (and if I missed anything).

I'm not looking for SAN vendor specifics, just more of a general flow.

For example, is that 2MB file broken up into 4K IO's (524,288 of them??) and are they all sent seperately over the fiber channel...etc..etc..

Any help or pointers you could provide would be greatly appreciated.

 

[blakerwry]

It sounds like you already have a good understanding of SANs in general and anything I can give you is already stated in the wikipedia article on SANs - http://en.wikipedia.org/wiki/Storage_area_network

The details you're asking for are largely implementation or vender specific. You can follow some of the links in the article linked above to get a better idea about how different SAN implementations vary and the details of each.