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Conference noted::decps

Title:POLYCENTER Performance Data Collector & Advisor for OpenVMS
Notice:Latest version V2.2-51
Moderator:BSS::JILSON
Created:Wed Nov 07 1990
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2413
Total number of notes:9017

2258.0. "2.2 Data Collector compute-bound, fails to terminate with ADVISE COLL STOP" by CSC32::K_JOHNSON () Thu Apr 04 1996 00:48

T.RTitleUserPersonal
Name
DateLines
2258.1Here's one...USPS::FPRUSSFrank Pruss, 202-232-7347Fri Jun 21 1996 05:233
2258.2Collector looping in 2.2CSC32::A_STEINDELTue Jul 16 1996 22:1716
2258.3Similar problem ?COMICS::MILLSSQuality bloke time and lager spaceTue Aug 06 1996 09:1923
2258.4ipmt in progress on thisCSC32::BUCKLEYski fast,take chances,die youngWed Jun 04 1997 14:1018
This looks very similar to the ipmt (C961205-932) that I have been working
for a long time. We do not have a fix (the ipmt is still attempting to collect
data on the problem for CA) but do know what seems to trigger it;

Very heavy io load (normally backup is running) with hotfiles data collection
enabled. The psdc$dc_server goes compute bound and no data is written out (or
the data is garbage- no reports can be run off the data). The collector will
normally recover after a while (when the io load decreases??) and data will be
written. While it is in the compute state, advise coll/stop/wait may not work
but $stop psdc$dc_server should.

workarounds that reduce the likelyhood of the collector going compute bound;

turn off hotfiles data collection completely (not acceptable to many customers)
change the hotfiles limit from .33 to 1.00 (only show real bad disks' hotfiles)
turn off hotfiles data collection during backup and turn back on after backup
reduce the number of concurrent backup/production jobs to reduce io load.
	(least acceptable to customers)