RE: You've heard it all before: newer, faster server runs slower than older, slower server after data migration

-----Original Message----- From: Obnoxio The Clown [SMTP:obnoxio@hotmail.com] Sent: Monday, November 20, 2000 6:29 PM To: aford@simpletel.com; informix-list@iiug.org Subject: Re: You've heard it all before: newer, faster server runs slower than older, slower server after data migration From: Andrew Ford <aford@simpletel.com> > >I've seen this problem many times in the news groups, and each time I've >said to myself, "That poor soul, someone spent a load of money for a new >server expecting a performance increase, only to find that the new server >runs dog slow. Thank God I don't have that problem." > >Help, I have that problem. > > >The basics, onconfig and some onstat output at end of message: >HP-UX billsvr1 B.11.00 U 9000/800 >Informix Dynamic Server Version 7.31.FC4 >8 Processors >4 Gig Ram >OLTP/DSS combo, OLTP more important than DSS. > >What we did: >We moved all Informix processing from an 8 Processor, 4 Gig Ram N Class >HP/UX machine to a 8 Processor, 4 Gig Ram N Class HP/UX machine. >The new configuration is connected to an XP256 with roughly 55 47 Gig >Drives and 11 15 Gig Drives (usable in a mirrored pair config) split into >1305 Informix Chunks which make up 454 Dbspaces. Mmmm...moved to XP256, you have? Runs now like dog, you say? Not RAID5, is it? [Andrew Ford] Nope, we avoid RAID 5 like the plague. We're using RAID1. >We started up ER in a Primary/Target config (the large N Class is the >server, replicating to 7 smaller targets), we initially used Unbuffered >logging (the old system used No Logging) but I recently set the logging to >Buffered to help speed things up a bit. Well, duh! That could be half the problem there. >Most of our code has been modified to use Isolation Dirty Read to cut down >on lock contention. ALTER TABLE xxx LOCK MODE (ROW);[Andrew Ford] All tables are defined with lock mode row. And it's got nothing to do with that shiny XP256, does it? ># Logical Log Configuration > >LOGFILES 96 # Number of logical log files >LOGSIZE 500 # Logical log size (Kbytes) These logs are *way* too small. [Andrew Ford] The logs we added via onparams at the command line are 230Meg each, does this ONCONFIG parameter have anything to do with how those logs are used? >RESIDENT 1 # Forced residency flag (Yes = 1, No = 0) Try -1 [Andrew Ford] We usually do set that to -1, but I recently had a problem with one of our servers needing to allocate another segment but it couldn't be forced resident. We decided that we would rather have the server up and running off swap space then crashed in the middle of the night. >NUMAIOVPS 1 # Number of IO vps Have you got KAIO enabled? :-) [Andrew Ford] Sure do, one thing that I've noticed is that an onstat -g ioq shows kaio doing all of the work, then proceeds to list 1300+ gfd (global file descriptor?) that are doing nothing. Are these used only if KAIO is DISabled? If so is there a way to avoid allocating these resources? If you haven't, that's your problem right there. As far as I can see, it looks OK, otherwise. [Andrew Ford] That's how I feel, we've also been talking to HP, it's possible that we have some kernel parameters that need to be changed. Thanks for the input. Andrew ________________________________________________________________________ _____________ Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com