We have no protected conversations, so it is more the reference to "serious performance degradation when running in limp mode" that may affect us. The questions of whether CRR could be stopped without causing the file pool servers to crash, and whether restarting the CRR machine while the file pool servers were running would restore normal operation were both addressed by Kris in an earlier post. In the absence of dissenting opinion, it appears that I will be able to move the CRR machine's disks with little or no noticeable effect, so long as I choose a lightly loaded period in which to do it.
Regards, Richard Schuh -----Original Message----- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Alan Altmark Sent: Wednesday, November 28, 2007 7:57 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: CRR Machine On Tuesday, 11/27/2007 at 11:39 EST, Alan Ackerman <[EMAIL PROTECTED]> wrote: > The question is, when are two-phase commits used? From what others > have told > you, one answer > is when you have R/W access to two different SFS filepools. The reference to a "protected conversation" is an APPC LU 6.2 SYNCLEVEL=SYNCPOINT conversation. It has a two-phase commit semantic built into it. Within a single CMS workunit you can, for example, open an SFS file (one file in one server, or multiple files, or multiple servers) and talk to one or more CICS LU 6.2 transactions (for example) over the network. When your application or one of the CICS transactions COMMITs the workunit, all files and transactions are committed or all are backed out. It doesn't matter whether you're doing this explicitly or not. The CMS file system will try to connect to the CRR server in *anticipation* of your opening a second file or establishing a syncpoint connection. Alan Altmark z/VM Development IBM Endicott
