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Bug 603565

Summary: 389 Directory Server Unnecessary Checkpoints
Product: [Retired] 389 Reporter: Ian Dall <ian>
Component: Directory ServerAssignee: Rich Megginson <rmeggins>
Status: CLOSED CURRENTRELEASE QA Contact: Ben Levenson <benl>
Severity: medium Docs Contact:
Priority: low    
Version: 1.2.6CC: andrey.ivanov, jgalipea, nhosoi, nkinder, rmeggins
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2015-12-10 18:37:53 UTC Type: ---
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 512820, 690319    

Description Ian Dall 2010-06-13 21:35:17 UTC 
Description of problem:

Even when there have been no logging activity, ns-slapd forces a checkpoint, generating unnecessary disk traffic.

Version-Release number of selected component (if applicable):

1.2.5

How reproducible:

Always

Steps to Reproduce:
1.On a quiescent system do "pidstat -C ns-slapd -d 60"

  
Actual results:
Disk writes are reported


Expected results:
No disk writes

Additional info:

Also "ls -lrt /var/lib/dirsrv/slapd-<server>/db" shows the log file and the __
db.nnn files regularly being updated.

This is apparently due to checkpoint being called (in db_layer.c:dblayer_txn_checkpoint()) with the DB_FORCE option.

Is there any reason to force these checkpoints?

I am using the server for user data (uid/gid etc) but not passwords (because I'm using kerberos for that). The ldap data hardly ever changes and I'd like to let the disks spindown in quiet times. An option, at least, to not force checkpoints would be nice.
Comment 2 Andrey Ivanov 2010-08-22 11:08:56 UTC 
There are at least two parameters that could help you :
nsslapd-db-checkpoint-interval and nsslapd-db-durable-transactions

Their descriptions are here :

http://www.redhat.com/docs/manuals/dir-server/ag/8.0/Tuning_DS_Performance-Tuning_Database_Performance.html#Tuning_Database_Performance-Changing_the_Database_Checkpoint_Interval

http://www.redhat.com/docs/manuals/dir-server/ag/8.0/Tuning_DS_Performance-Tuning_Database_Performance.html#Tuning_Database_Performance-Disabling_Durable_Transactions
Comment 4 Martin Kosek 2012-01-04 13:31:23 UTC 
Upstream ticket:
https://fedorahosted.org/389/ticket/84