Thanks for the answer. 1) Make sure you have sufficient paging space to back CP allocating 1G of pages per guest. The initial allocation that comes with VM isn't big enough, and while you won't use it all at once, you WILL eventually need it.
I have one mod9 and 6 mod3 for paging (total pages 5281K) - abo0ut 38% used right now. Would this be sufficient ? Alan Levy VM/Linux Administrator W: 718-403-8020 C: 347-401-4629 -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of David Boyes Sent: Tuesday, February 27, 2007 4:36 PM To: [email protected] Subject: Re: Vdisk > (For Bennie :-)) Wherever we may find him. Thanks, Simon & G. 8-) > How would you define a 1G swap space with vdisk ? 1) Make sure you have sufficient paging space to back CP allocating 1G of pages per guest. The initial allocation that comes with VM isn't big enough, and while you won't use it all at once, you WILL eventually need it. 2) Update SYSTEM CONFIG to remove the limit on VDISK allocation. The statement is already there in newer VMs, just commented out. It has a nice comment block near it so you know which one to use. 3) Divide 1G by 512 bytes. This gives you the number of blocks needed for the VDISK. 4) Download SWAPGEN EXEC from www.sinenomine.net. 5) Set your Linux guests up to IPL CMS first, then put a call to SWAPGEN into their PROFILE EXEC. The syntax of SWAPGEN is documented in the comments in the exec. 6) Once SWAPGEN defines the VDISK and puts a Linux swap signature on it, the last thing to do in the PROFILE EXEC is to have the machine IPL Linux. > I have about 30 linux servers, each with about 1G swap on physical dasd. > Can I use Vdisk for each of them ? Yes. VDISK is allocated a 4K page at a time, as it's actually used, not all at once. It's also pageable, so CP can flush out unused stuff to CP paging space if it needs elbow room. > Can a 3G system handle 30G (or more) of vdisk ? As long as your guests don't try to use all 30G at once, yes, but you should keep a closer eye on your Linuxen; if they start swapping hard enough to chew through a gig of swap, there's something else evil going on. The trick is not to actively use all your real storage for VDISK -- you can define more VDISK than you have physical RAM, but you don't want to use it all at once. You definitely need to be sure you have CP paging space sufficient to back all the allocated VDISK you define, though -- that's just a good safety net. > What would be the > system limit ? User limit ? Personally, I turn the system limit off. The user limit should be what you have allocated, so I don't really use that limit either. Others have pointed you to redbooks; there are also good comments in SWAPGEN EXEC on how to do it as well. ---------------------------------------------------------------------- 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
