I was just going throught ISM Ch 2 and suddently a thought came to me.
Does the IO size changes from Application to when it reaches SAN/DISK.
We all know that OS comes in between .
(Except for application which uses RAW Lun , and for these I believe it reaches to SAN as it is, means same size say 4 KB).
The Reason for my Doubt is that every OS keeps a File system Cache in physical memeory and files are actually mapped at run time from Memory to file system and in turn to SAN by OS.
Isnt is that Os can combine various IOPS for effieciency and optimisation .
OS can combine IOPS across two applicaiotions at the same time , and send it across , if they are for the same volume or target device ?
Does it really happen like this or not is a question ??
The OS running on Different Storage Boxes varies in terms of their functionality, eg
The Clariion Environment is governed by FLARE Code and the Symmetrix / DMX by Enginuity Code.
As you progress with the chapters, you will find a clear picture
Actually I was referring to Caching which is done in the host (Server). Windows and linux have a file system cache.
More precisely http://msdn.microsoft.com/en-us/library/windows/desktop/aa364218(v=vs.85).aspx
Flare and Dart I am going into .
Am trying to know how the OS (HOST , LINUX, Windows) manipulate an io (from App) before it reaches to intelligent storage systems.