What is the maximum BLKSIZE that user can give for a file
The number of bytes that you specify for BLKSIZE depends on the device
type, the record format for the data set and other programs that will
read or write the data set. The maximum value that you can code is
2,147,483,648 (coded without the commas) or 2G
My 2 Cents :
The SMS is smart enough to decide the optimal blocksize for the given record structure.. So, unless its very important, its advisable to not to specify blocksize while creating a new dataset.