Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!ox.com!math.fu-berlin.de!unidui!unido!sapwdf!wohler From: wohler@sapwdf.UUCP (Bill Wohler) Newsgroups: comp.unix.aix Subject: mathematics of swap space Message-ID: <2758@sapwdf.UUCP> Date: 22 Apr 91 11:38:59 GMT Reply-To: Bill Wohler Organization: SAP AG, Walldorf, Germany Lines: 61 swap space gurus: with 128M of real memory and 208M of swap (and effective total of 336M of memory!) on a 530, i would not have expected to see "INIT: swap space low", especially considering when the sum of the SIZE column of "ps uax" is only 58M. ps uax | awk '{sum += $5} END {print sum}' 57876 researching this problem via info revealed the following numbers: [wohler@aix3:175]% lsps -a Page Space Physical Volume Volume Group Size %Used Active Auto paging00 hdisk1 uservg 64MB 65 yes yes hd6 hdisk0 rootvg 144MB 34 yes yes --- 208 [root@aix3:201]# vmstat procs memory page faults cpu ----- ----------- ------------------------ ------------ ----------- r b avm fre re pi po fr sr cy in sy cs us sy id wa 1 0 24401 11756 0 0 0 0 2 0 117 55 37 1 1 96 0 24401 (avm) * 4096 = 96604k 11756 (fre) * 4096 = 47024k -------- 144628k these numbers and info raise the following questions which info couldn't answer. i'd be very thankful for any of your answers: o what percentage of paging space free is considered to be a low condition (ie. SIGDANGER's sent to processes)? o is the total amount of available virtual space just the swap space, or real memory plus swap space? o what program is used to determine how much real memory the system thinks it has? o why is the swapper process so large? o why is the total amount of available and free memory displayed by vmstat not equal to 208 displayed by lsps? o why is there such a discrepancy between the sum of the SIZE column of ps and the avm field of vmstat? in summary, do these numbers indicate a bug or a broken configuration? why did the system indicate that we ran out of swap space? what other tools do we have at our disposal? -- --bw ----- Bill Wohler Heidelberg Red Barons Ultimate Frisbee Team