Re: Informix/Solaris Kernel Parameter (semsys:seminfo_semmni)

On 26 Feb, 06:20, "Jonathan Leffler" <jleffler.i...@gmail.com> wrote: > On 23 Feb 2007 07:53:01 -0800, Dave <In4Mix...@gmail.com> wrote: > > > > > > > We are running Informix 7.31 on a Sun Solaris 8 server. This week we > > moved our production Informix server to a different Sun Solaris 9 > > server. We noticed that 2 of the Kernel parameters were set > > differently. > > > Old Server - Solaris 8 > > semsys:seminfo_semmni=100 > > shmsys:shminfo_shmmin=1 > > > New Server - Solaris 9 > > semsys:seminfo_semmni=4096 > > shmsys:shminfo_shmmin=100 > > > I checked the release notes for 7.31 and the recommendations are the > > way we had it configured on the old Server. > > > What do these 2 (semsys:seminfo_semmni, shmsys:shminfo_shmmin) kernel > > parameters do or what are they related to?? > > > Also, our production environment is running very well on the new > > system. Only 2 items we noticed different are checkpoints are taking > > between 3 and 6 seconds longer and there are between 50,000 and > > 200,000 more latch request waits per hour (lchwaits from onstat -p). > > As J P Renaut said: > > > seminfo_semmni on solaris is the maximum number of semaphore > > identifiers for the system. > > shminfo_shmmin is the minimum size of a shared memory segment, > > in bytes. > > The values mentioned in the release notes are suggestions, not > commandments. Being able to have more semaphore sets won't cause > problems for IDS; I suppose it might waste a little system resource, > but you're unlikely to be able to measure it. > > The minimum size of a shared memory segment is more intriguing. IDS > won't be using small size shared memory segments - not in the > sub-kilobyte range - but some other parts of Solaris do. In > particular, I seem to remember the powerd (power daemon) using 16 or > 20 bytes in Solaris 7, but just 4 bytes in Solaris 8. So, I had > shmmin set to 4 - but 1 is a perfectly reasonably alternative, quite > honestly. You won't see a problem with large values of shmmin unless > you monitor your boot logs (/var/adm/messages, IIRC). > Why do the release notes not recommend shmmin 1 then? I asked for this around 1996 when I first found the powerd issue if shmmin is set to 100! > -- > Jonathan Leffler #include <disclaimer.h> > Email: jleff...@earthlink.net, jleff...@us.ibm.com > Guardian of DBD::Informix v2005.02 --http://dbi.perl.org/ > NB: Please do not use this email for correspondence - I don't read it > every week, even.- Hide quoted text - > > - Show quoted text -