rgc@wam.umd.edu (Ross Garrett Cutler) (08/08/90)
Hello, I recently did a generic (default) setup of Ultrix 3.1d on a DS3100 w/8 MB RAM and an RZ55 (300 MB HD). I just did a pstat -s, and it said that 64 MB was allocated for swap space! Now I always thought that you should allocate about double the installed RAM, but not 8 times! Note that ~11 MB was currently being used in an idle 1-user state (most likely because of that RAM-hog DEC Windows). Anyway, are there any recommendations as to how much swap we should allocate? On a similar front, we also have a VS3200 running Ultrix 3.0 w/8 MB RAM. We have 16 MB of swap space allocated; if we try to run two programs that should not fill up the swap space (each uses about 1 MB of text and data combined), we get messages like "out of core". Has anyone else had this problem? And how much swap space (in general) is recommonded for this system? Thanks much... -- Please email -- I'll summarize. Ross Cutler University of Maryland, College Park Internet: rgc@wam.umd.edu
grr@cbmvax.commodore.com (George Robbins) (08/09/90)
In article <1990Aug8.165421.27886@wam.umd.edu> rgc@wam.umd.edu (Ross Garrett Cutler) writes: > I recently did a generic (default) setup of Ultrix 3.1d on a DS3100 w/8 MB >RAM and an RZ55 (300 MB HD). I just did a pstat -s, and it said that 64 MB was >allocated for swap space! Now I always thought that you should allocate >about double the installed RAM, but not 8 times! Note that ~11 MB was >currently being used in an idle 1-user state (most likely because of that >RAM-hog DEC Windows). Anyway, are there any recommendations as to how >much swap we should allocate? With windowing on the RISC based systems, you should allocate lots of swap space - I'd say at least 4X for a personal system, more if you get into multi-tasking, emacs or applications abuse. Actual allocation is probably derived from standard disk partitions, rather than any configuration dependent "need", so you might want to tune it a bit. >On a similar front, we also have a VS3200 running Ultrix 3.0 w/8 MB RAM. >We have 16 MB of swap space allocated; if we try to run two programs that >should not fill up the swap space (each uses about 1 MB of text and data >combined), we get messages like "out of core". Has anyone else had >this problem? And how much swap space (in general) is recommonded for this >system? You need to take a look at all the swap space requirements for all the active processes. Ultrix allocates swap space for each process, whether or not it needs it, so you may find the sum taken up by extra logins, daemons, etc to be more than you expect. The units of allocation are controlled by the dmmin and dmmax config parameters. For swap constrained systems, you want to make sure that dmmin is large enough that getty and the like fit within the iniital allocation, elsewise they start chewing into the dmmax units... There may also be some fragmentation issues, but I haven't dug into it that deeply. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)
hubcap@hubcap.clemson.edu (System Janitor) (08/09/90)
So - With all this talk about swap going on, what do you think of this?... My config file looks like: config vmunix root on ra0a swap on ra0b and ra1b and ra2b dumps on ra2b My fstab has: /dev/ra1b::sw:0:0:ufs:: /dev/ra2b::sw:0:0:ufs:: And I've got ``swapon -a'' in /etc/rc... But at boot time (or anytime I type ``swapon -a'' or ``swapon /dev/ra1b'') I get: ``/dev/ra1b: No such device'' The Advanced Installation Guide (on page 2.5) sez: ``The advanced installation lets you allocate two swap areas: swap1 and swap2. (You can allocate additional swap space during day-to-day system management. See the Guide to System Disk Maintenance for instructions on how to do this.)'' So maybe I shouldn't have three swap areas defined in my config file, but the promised info in the Guide to System Disk Maintenance about allocating additional swap areas is not to be found... any ideas?... -Mike
grr@cbmvax.commodore.com (George Robbins) (08/10/90)
In article <10063@hubcap.clemson.edu> hubcap@hubcap.clemson.edu (System Janitor) writes: > With all this talk about swap going on, what do you think of this?... > My config file looks like: > > config vmunix root on ra0a swap on ra0b and ra1b and ra2b dumps on ra2b > > My fstab has: > /dev/ra1b::sw:0:0:ufs:: > /dev/ra2b::sw:0:0:ufs:: > > And I've got ``swapon -a'' in /etc/rc... > > But at boot time (or anytime I type ``swapon -a'' or ``swapon /dev/ra1b'') > I get: ``/dev/ra1b: No such device'' Interesting question... The actual swap configuration from the config file goes into /sys/{MIPS/}swapvmunix.c, and puts hard coded major and minor numbers in a table. You get the "No such device" if you're adding an area already in use, but might also get it if the partition wasn't allocated or if you don't have an appropriate /dev entry for the device - it may be that swapon makes some references to the /dev entry before issuing the "swapon" system call. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)
wright@mdcbbs.com (08/16/90)
In article <10063@hubcap.clemson.edu>, hubcap@hubcap.clemson.edu (System Janitor) writes: > My config file looks like: > > config vmunix root on ra0a swap on ra0b and ra1b and ra2b dumps on ra2b > > My fstab has: > /dev/ra1b::sw:0:0:ufs:: > /dev/ra2b::sw:0:0:ufs:: > > And I've got ``swapon -a'' in /etc/rc... > > But at boot time (or anytime I type ``swapon -a'' or ``swapon /dev/ra1b'') > I get: ``/dev/ra1b: No such device'' > I don't believe the three swap areas should have any affect on the overall swapping or should bother the system. Although I would remove the "swapon -a" from the rc.local, you don't really need it. And for simplicity sake your entries in /etc/fstab only need look like the following: /dev/ra1b::sw::::: /dev/ra2b::sw::::: The system only cares what partition when it sees the "sw" in the type field. The way to find out if your "configured" swap areas are seen by the system is to check two lines when you do a pstat -s: 131072k swap configured 57162k used (12668k text, 1312k smem) 75408k free, 12060k wasted, -1498k missing avail: 36*2048k 1*1024k 2*128k 1*64k 3*32k 7*16k 128*1k 131072k swap configured ^^^^^^^^^^^^^^^ shows how much swap you should have, in this case /dev/rz0b and /dev/rz1b (rz55's) 57162k used (12668k text, 1312k smem) 75408k free, 12060k wasted, -1498k missing ^^^^^^^ shows how much is not recognized by the system, this means it's configured but not in use. avail: 36*2048k 1*1024k 2*128k 1*64k 3*32k 7*16k 128*1k -- +----------------------------+-----------------------------------------+ | Dave Wright | Phone: (714) 952-6320 | | McDonnell Douglas M&E | Internet: wright@mdcbbs.com | | Software Engineering | UUCP: uunet!mdcbbs.com!wright | | P.O.Box 6011 | PSI: PSI%31060099980019::WRIGHT | | Cypress, Ca. 90630 | | +----------------------------+-----------------------------------------+