Tom, First off, can you point dynamic allocations to a specific SC? - If so I'm sorted as we already have a particular SG that has every volume set to DONOTBLOCK. If you can specify SC for dynamic alloc's then I have an SC that points to this SG.
The problem is, these datasets do require, and generally get, very good performance. The fly in the oitment is when XRC gets involved. If XRC can't keep up with the primary cache, it slows down the primary dasd by applying the brakes either at device or session level. There's nothing we can do about session level blocking and as long as we keep the sessions balanced, it's so rare as not to be a problem. However, if a device exceeds the X'500' threshold (how many tracks behind is XRC?) XRC blocks a particular volume. So, if these datasets go to a hot volume, the potential of XRC blocking the device increases. Most batch jobs can live with device blocking, these datasets can't. That means we have to set the volumes containing these datasets as DONOTBLOCK in case they happen to exceed the X'500' threshold. Pretty tough if the dataset is going to move when it is DEL/DEF each evening. We'll end up blocking/unblocking on a daily basis. Not my preffered option. I'm not too hot on dynamic allocations so if we CAN point a dynamic allocation to a particular SC (there's no JCL) then I haven't got a problem. Regards, JJ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
