1. BDII Performance Tests
Felix Ehm
CERN IT/GD

2. Content The BDII GLUE Schema BDII Performance Tests Future
Introduction
Architecture
GLUE Schema
Purpose
Latest News
BDII Performance Tests
Reasons
Test Setup
Relational vs. LDAP backend
Results
Future
Felix Ehm, CERN 2008

3. The BDII
Felix Ehm, CERN 2008

4. The BDII What is it ? What is it used for ? Who uses it ?
Berkley Database Information Index
Main purpose : provide a way to discover services in a Grid Infrastructure
Evolved from Globus MDS
Uses the OpenLDAP server (and Berkley database) internally
What is it used for ?
Publishing resource/service status info
Matchmaking of jobs/resources
Monitoring
Accounting
Who uses it ?
nearly every gLite component (SE, CE, WMS, UI, ..)
Felix Ehm, CERN 2008

5. The BDII Architecture One core component (BDII)
Site-, Resource- and Top-Level BDII only differ by their configuration
Information flow follows ‘pull’ principle
Uses OpenLDAP to pull/store/provide information
Example for Top-Level:
Information Flow
Incoming Requests
Serving old requests
Port forwarder
BDII
Serving new requests
Provider
Site-BDII
Site-BDII
Site-BDII
Felix Ehm, CERN 2008

6. GLUE Schema
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7. GLUE Schema What is it ? Latest News :
Grid Laboratory Unified Environment
defines a common conceptual data model to be used for Grid resource/service discovery
Working group part of the OpenGridForum (OGF)
Available as Version 1.3 ( )
Latest News :
GLUE 2.0 in progress :
Elaborated in respect of 1.3 problems
Not backward compatible to 1.3
Computing schema almost finished
Storage schema now hot topic
When deployed ?
Felix Ehm, CERN 2008

8. BDII Performance Tests
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9. BDII Performance Tests
Why ?
No existing performance characterization
User complains about request timeouts
What do we test ?
Request handling rate
Effects on data size (currently 250 sites ~ 30Mb)
How well do we scale (when do timeouts occur) ?
In fact, we test the OpenLDAP server
Felix Ehm, CERN 2008

10. BDII Performance Tests
Test setup:
9 dedicated worker nodes
Issuing parallel a number of one/mixed queries
against 1 top level BDII instance
for a time period of x seconds
15 sec timeout limit
Bunch of bash scripts for
Preparing the machines
Executing the test
Tune test results
Ignore results at beginning
Watch the system in a ‘stable’ state
Felix Ehm, CERN 2008

11. BDII Performance Tests
Relational vs. LDAP data model test setup
LDAP2SQL conversion tool (
30K LDIF entries ~120K rows
MySQL 4.1, same hardware as OpenLDAP server
Oracle 10.2 RAC, 2 node database cluster
Also tested for completion
Native OpenLDAP client connects, searches, disconnects
Diffcult to do the same for relational database
Not a normal scenario for a relational DB
Felix Ehm, CERN 2008

12. BDII Performance Tests
Client Execution Time Test
Which client implementation for LDAP vs. relational model test ?
Reason
Minimize client execution latency
Find common client
Comparison:
Result
No common (fast) implementation
PERL for relational
Native OpenLDAP client for LDAP
Felix Ehm, CERN 2008

13. BDII Performance Tests
Results
BDII Performance Tests
Felix Ehm, CERN 2008

14. Results OpenLDAP server with indexed/nonindexed DB
Indexed DB nearly 100 times faster then nonindexed
CPU load on indexed DB ~10 times lower
More CPU capacity for other requests to handle
Felix Ehm, CERN 2008

15. Results Comparison of OpenLDAP Software
2.2 (SLC4), 2.1 (SLC3) and 2.2 on 4 core machine
Version 2.2 scales much better than 2.1 on same hardware
At 90 parallel requests ~ 20% faster than 2.1
Version 2.2 on 4 core machine
~ 65% faster than on DualCore ( % speedup/core)
~ 117% faster than 2.1
Felix Ehm, CERN 2008

16. Results
Multiple Queries issuing against a running top-level BDII instance with 3 switching DBs
Felix Ehm, CERN 2008

17. MySQL, Oracle and LDAP multi query results
Each worker node spawns one request continuously
Felix Ehm, CERN 2008

18. Result Effect of Data Size Currently ~ 30Mb
OpenLDAP serves data very well (close to network interface limit):
Clients retrieve requested information within the given timeout (15s)
Datasize:
100K
1MB
10MB
Parallel Requests:
~2000
~200
~18
Felix Ehm, CERN 2008

19. Result Relational Model vs. LDAP
Returned data size different although information content is the same
OpenLDAP server sends also the objectclass and attribute names
Small dataset (169 Entries)
MySQL ~70% faster
Oracle ~429% faster
Big dataset (8185 Entries)
MySQL ~411% faster
Oracle ~1500% faster
Felix Ehm, CERN 2008

20. Conclusion BDII However: Indexes help a lot to improve performance
Handles ~100 parallel requests with small dataset very well (< 2sec)
Clients are advised to use queries which result in a small dataset
NO (objectClass=*) SEARCHES !
However:
Adding full content every refresh cycle loads the machine
Implementations of a relational model showed better performance
should be considered for future developments
Felix Ehm, CERN 2008

21. Future
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22. Future Compressed content exchange
Data is exchanged in compressed format
30MB LDIF is reduced to 1.4MB
Speeds up fetching data from site-level BDIIs
Decrease information age
Prototype ready
Splitting dynamic and static information
Reduce amount of data being populated
More Information on plans :
Support :
Felix Ehm, CERN 2008

23. Questions ?
Felix Ehm, CERN 2008