Re: IDS 10 erratic run times

On Mon, 19 Sep 2005 01:01:44 +0100, "Neil Truby" <neil.truby@ardenta.com> wrote: >IDS 10.0FC3 on Solaris 2.9 > >This is a brand new server which we are preparing to migrate a v9 system to. >Over the past few weeks I have run multiple dbimports from more-or-less the >same data source - certainly the same schema - but the import time varies >widely. > >The fastest I've done it is 9h, the slowest 14. This weekend's took 13h >10m. There's never anyhting else going on on it. In the UPDATE STATISICS >phase the elapsed time was 3h: during the "fast" run it was just 1h. I had >a look during this period: often onstat -p onstat -m onstat -D would show >periods of perhaps 2 minutes with no activity at all: no bufreads or >physreads, no checkpointing for 20 minutes (the checkpoint interval is 5 >mins), the relevant thread just "sleeping forever". > Waiting for disk, perhaps? Something at the OS level? >I haven't changed the disk layout (a 60G database striped across three disks >in a JBOD array with the standard Solaris LVM interlace of 16k, this stripe >mirrored to another 3 disks identically configured attached to another >controller on the same array); I have experimented with different buffer >sizes (perversely one 9h run was with BUFFERS set to just 100,000 rather >than the usual 1,000,000 although there's no consistent pattern to this now >I've cut the LRU MIN and MAX, and I've had another 9h run with the 2GBytes >of BUFFERS since). > >It's the fact that all activity just seems to stop for long periods that >puzzles me. If, during such a period, I fire up dbaccess and run a sysmater >query it returns instantly, so I can't see a systemic cause. The new box is >still 1.5 to twice the speed of the old in comparative testing but this >disparity in times is just puzzling me and I don't want it to come back and >bite us after go live. > What are the oninits doing? Percentages? Just a few thoughts . . . . JWC

ahum you may want to check what is slow. in the past there were problems with spl's this caused one to get grey hair.... SLOWWWW.... w.a. was before export to dbschema them all (do not forget permissions) drop 'm all export and import and after that recreate them all so please check what import is doing at that point. Superboer.

Neil, I have seen anything similar when we had AUTORAID configured on a system Sometimes the disks ran as RAID 10 and other times as RAID 5 depending how the AUTORAID decided to configure them When RAID 10 the performance was great When RAID 5 our perfromance was woeful

"scottishpoet" <dryburghj@yahoo.com> wrote in message news:1127128089.906988.42210@g43g2000cwa.googlegroups.com... > Neil, > > I have seen anything similar when we had AUTORAID configured on a > system > > Sometimes the disks ran as RAID 10 and other times as RAID 5 depending > how the AUTORAID decided to configure them > > > When RAID 10 the performance was great > > When RAID 5 our perfromance was woeful > Interesting. I'm sure this is a permanent RAID 0+1. And the performance is not exactly consistently slow, more stop-start. I will check this out. At the moment the situation is to vague to raise a support call with IBM, and it has to date resisted my attempts to reproduce a smaller case. We're continuing to try to build a reproducible case, and see it's just a 10.0 thing (no reason to believe is it at this point). I've had a few cases in the past couple of years when we've painstakingly built a case then been told almost immediately by IBM we've hit a known problem. How I wish there was still the facility of TechInfo, where we mortals can check this out for ourselves at the outset. If anyone from Tech Support is reading, could I ask them if there are any known bugs in IDS 10.0 consistent with our symptoms? thanks Neil

There is a facility like TechInfo http://www-306.ibm.com/software/data/informix/ids/support/