Leslie , I think Rob might be trying to warn you of a risk that a DEVNO MDISK exposes your system to during a VM IPL.
During IPL, CP looks at the dasd devices in address order and for a given volid referenced by SYSTEM CONFIG, CP uses the first dasd it finds having that volid; if the same volid is found again on a higher address dasd CP says it's found that one as a duplicate volid and doesn't attach it to SYSTEM. The risk is a guest with a DEVNO MDISK could change its volid (by accident or intent) to a value that causes CP during the next IPL to pick it first instead of the correct higher address dasd with that volid. You can use DEVNO MDISKs and protect the system against the risk by coding SYSTEM CONFIG to put the DEVNO MDISK addresses OFFLINE_AT_IPL, like Offline_at_IPL 0200-0203 /* DEVNO MDISKs - dupe volid risks */ Then in AUTOLOG1's PROFILE or wherever convenient you put commands to have CP VARY ON devno1 devno2 devno3-devno4 -------------------------------------------------------- This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments. Please notify the sender immediately by reply e-mail and delete the e-mail from your system. -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of J Leslie Turriff Sent: Wednesday, November 01, 2006 5:36 PM To: [email protected] Subject: Re: New DASD When using DEVNO, the volume's VOLSER is not consulted, and the volume must not be attached to SYSTEM. The rdev value following the DEVNO keyword refers to the real device number of the volume. Leslie >>>Rob van der Heij <[EMAIL PROTECTED]> 11/01/06 8:54 am >>> On 11/1/06, J Leslie Turriff <[EMAIL PROTECTED]> wrote: >I know that I'm probably in the minority here, but I like to use the > >MDISK vdev 3390 DEVNO rdev md rp wp mp > >statement, which allows one to map a volume's virtual address to its >real address as the DEDicate statement does, but makes it clearer which >address is which, and as a side benefit allows sharing the volume if >desired. I use the more conventional MDISK statement only when mapping >minidisks. And you accept the risk that someone would put a label on that disk and confuses CP at next IPL. Suppose he picks the label of the volume that has your 190 disk, and would put a slightly modified version of your 190 disk on the right spot on that user pack... Or match the label of CP owned volume and confuse spool, break paging, etc. Or match the label of a z/OS disk... Depends on who you can trust and who has access to these servers. Rob ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
