Read pattern of TChain


we have a file system with a block size of 4MB and want to access root files on this file system directly. This means we want to read in the data in relative large chunks of at least 4mb to use our full i/o performance. It seems that root accesses the files in ~10kb up to 1mb packets. We tried to change this by using SetCacheSize() for the TChain but this seems not to change the read pattern.

Is there any way to tell a TChain to access the root file in larger packets ?