I depends on how you've got it set up and what controls you have in place. If you're using VM as a hypervisor for Linux, VM has to be able to know what the volser of the DASD is. If your linux instances have root authority not controlled by you and they take it in mind to do a dasdfmt on a full-pack disk, including cylinder 0, and change the volser in doing so, then the next time VM is IPLed, that pack might not be found and the linux instance won't come up because the directory won't match the volser.
"Nature and nature's laws lay hid in night: God said, 'Let Newton Be!' and all was light." - Alexander Pope "It did not last; the Devil howling 'Ho! Let Einstein Be!' restored the status quo." - John Collings Squire "God Rolled his dice, to Einstein's great dismay: 'Let Feynman Be!' and all was clear as day." - Jagdish Mehra Gordon W. Wolfe, Ph. D. VM Technical Services, The Boeing Company > ---------- > From: Steve Gentry > Reply To: Linux on 390 Port > Sent: Wednesday, March 17, 2004 10:13 AM > To: [EMAIL PROTECTED] > Subject: Re: Let Linux use Cyl 0? > > I do not think you should let anything other than VM itself use cyl 0. As > this is where VM keeps Vol id, disk map info, etc. $ALLOC$ is what is > some times called a place holder. The userid $ALLOC$ doesn't actually do > anything with it other than mark it or inform others that this cylinder is > occupied. I also set up a $EOV$ on each volume on the last cylinder to > help with keeping track of gaps that DISKMAP will show. > Steve Gentry > > > > > > "Davis, Larry" <[EMAIL PROTECTED]> > Sent by: Linux on 390 Port <[EMAIL PROTECTED]> > 03/17/2004 11:50 AM > Please respond to Linux on 390 Port > > > To: [EMAIL PROTECTED] > cc: > Subject: Let Linux use Cyl 0? > > > Should I be letting Linux instances, under z/VM, utilize Cylinder 0? > Currently I allocate Cylinder 0 to $ALLOC$ and the rest of the volume to > the > Linux image. > I CPFMTXA cylinder 0 in VM and give it a VOLSER. Then, I access the > devices > under Linux and dasdfmt them, and partition them using fdasd. > > Until I get FCP and an ESS setup to allocate larger volumes, I will be > using > LVM for the larger file systems. I am planning to take full volumes of > 3390-3 DASD and create Logical volume groups from them. I can split the > devices between 4 FICON channels and 2 Controllers. > > Any recommendations? > > TIA, \|/ > (. .) > ____ooO-(_)-Ooo____ > Larry Davis, 6-2380 > > > ---------------------------------------------------------------------- > 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
