Q VDISK USERLIM .. and Q VDISK SYSLIM to see any system maximums set (sounds like one or both are). Use CP SET VDISK USERLIM INFINITE if you don't want maximums set .. (or use a value you are comfortable with). Same with SYSLIM...
Do a HELP CPSET VDISK to read up on the values, etc... Scott Rohling On Mon, Dec 30, 2013 at 8:29 AM, Levy, Alan <al...@doitt.nyc.gov> wrote: > One last question on swap. If I have to set up a 4G swap space, how do I > do it ? > > I tried using swapgen to define a 2G (4194304 blks) space and it says > "vdisk space not available" > > I looked online and found someone saying that the maximum on a single swap > is 4194296. > > > -----Original Message----- > From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of > David Boyes > Sent: Monday, December 30, 2013 10:12 AM > To: LINUX-390@VM.MARIST.EDU > Subject: Re: oracle question > > > Thanks for all your answers. I guess I'll give him another vdisk of 4G > > and if he needs more, I can "swapgen" another vdisk. > > Yeah, small incremental increases usually are good thing. > > > Is one 8G swap device better than 4 2G swap devices ? It's a lot > > easier adding another swap device than having to increase an existing > swap. > > Since there can be only one outstanding I/O for a device number in the > s390x architecture (putting PAV aside, since it doesn't apply to VDISK), > having more than one device _usually_ works better. VDISK is really, really > fast, but having options for Linux to initiate multiple page I/O requests > can help. > > One pattern I've seen used repeatedly is: > > 3 swap disks in priority order (see the man page for swapon): > > 1. VDISK half size of main memory > 2. VDISK size of main memory > 3. Real MDISK size of main memory. > > The VDISKs don't take up space unless they're actually used. You monitor > swap usage, and if you ever get more than half way into the 2nd VDISK, time > to up main memory size. If you get into the real MDISK, things will get > really icky really fast -- something your automation should be checking. > > Keep an eye on the amount of VM paging space you have allocated too -- if > you get a workload spike with lots of VDISK active, that's where it comes > from, and if you run out, Bad Things happen. A good target is to have VM > page space about 50% full at max, again multiple smaller devices may > perform better than larger devices. > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, send > email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit http://wiki.linuxvm.org/ > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
