Re: onperf vs onstat information

From: mars1972@my-deja.com > >In article <8d1shb$e1n$1@nnrp1.deja.com>, > Mister Creosote <glynb@my-deja.com> wrote: > > I am struggling to make sense of some info I am being presented with >by > > onperf and onstat. > > > > onstat -g seg output :-> > > > Informix Dynamic Server Version 7.31.UC2 -- On-Line -- Up 00:04:25 >-- > > 188416 Kbytes > > > > Segment Summary: > > id key addr size ovhd class blkused >blkfree > > 509 1381451777 82000000 58720256 1748 R 6688 480 > > 510 1381451778 85800000 134217728 2640 V 380 16004 > > 511 1381451779 8d800000 4194304 656 M 54 458 > > Total: - - 197132288 - - 7122 16942 > > > > Am I readng this wrong, or does the final section in the first line > > mean I have some 188416Kb of Shared Memory allocated to this instance? > > If this IS the case, how come onperf/tools/status for this instance > > shows only some 2.97Mb rather than 184Mb? I'm sure this is a simple >one > > so accept my apologies in advance. The main reason for the question is > > that we have some 640Mb physical RAM in the machine which is dedicated > > to IDS (aren't we all?) and I want to maximise the use of this RAM. > > Could someone also explain the use of the SHMVIRTSIZE entry in > > $ONCONFIG - again my understanding is that this is the initial size of > > the virtual shared memory segment (in Kb) - that being the case, our > > values do not equate to what I am seeing above. > > > >Yes, that 184MB is the total amount currently taken up by shared memory, >but it isn't solely dependant on SHMVIRTSIZE. Once that memory runs >out, Informix starts allocating additional blocks, each block equal to >SHMADD, up to a maximum of SHMTOTAL. You have SHMADD set to 8MB, so it >looks like you have allocated 7 additional segments. It would be a good >idea to increase SHMVIRTSIZE to about 10% more than the 188416 so that >Informix doesn't have to use that fragmented shared memory, since it >becomes less efficient when it has to allocate more than 1. >Doing this will make Informix start out with 200000 KB of memory >or so. Another good idea would be to change your SHMTOTAL to around >512000. This will keep informix from trying to allocate more memory >than exists on the box, and it will prevent Informix from allocating too >much memory. If you don't, it's possible that Informix will take up all >(or close to all) of the memory on the box, not leaving any for the OS >or other applications that run on the box. (Things that run from cron, >OS, backup stuff, that sort of thing.) Huh? Informix Dynamic Server Version 7.31.UC2 -- On-Line -- Up 00:04:25 -- 188416 Kbytes Segment Summary: id key addr size ovhd class blkused blkfree 509 1381451777 82000000 58720256 1748 R 6688 480 510 1381451778 85800000 134217728 2640 V 380 16004 511 1381451779 8d800000 4194304 656 M 54 458 Total: - - 197132288 - - 7122 16942 Where do you see additional segments? I think you forgot about the resident portion. :-) 188416 = R + V (KB) 19732288 = R + V + M (bytes) ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com