On Wednesday, 04/11/2007 at 08:14 EST, RPN01 <[EMAIL PROTECTED]> wrote: > Doing the DIRECTXA command changes between the pair of directories within > the DRCT area. Would the second system notice the change via the Diag? I can > see where doing a second DIRECTXA could cause serious problems. Are you > saying that if you do it to some other random pack, that would be enough to > cause the second system to re-read the real dierctory?
There is no serialization in CP to protect the directory from damage by a second system. I would recommend that the fullpack minidisk that overlaps the directory cylinders be (a) protected by cross-system links (XLINK), and (2) protected by your ESM to prevent MW. At least that way you ensure only one user in the cluster has write access to the directory to perform DIRECTXA. Then you must guarantee another DIRECTXA is not started until the Diag 0x3C has been successfully issued on ALL of the other systems in the cluster. I don't want to envision the carnage if CP reads the directory index and by the time he locates what he wants, the active directory has been rewritten and the index he read is no longer valid. I'll just say "Eeeew!" and leave it at that. [In order to maintain the PG-13 rating of this forum, the MPAA will not allow a more graphic description.] If the communications link between the cluster members goes down, you can no longer update the shared object directory. > Actually, with DirMaint and its dirmsat partner, keeping the two directories > isn't really a problem, and I don't have to log into the other system to > take care of the directory. Programmers are essentially lazy people, so I > don't want to recreate work that I can have handed to me.... You can make a shared object directory work, but the penalty for failure could be severe. Given the existence of things like DirMaint's cluster directory management capabilities, I would ask "Is the benefit worth the risk and the effort?" Alan Altmark z/VM Development IBM Endicott
