Transcript Shamardin
LCG/gLite BDII performance measurements
Lev Shamardin
[email protected]
Scobeltsyn Institute of Nuclear Physics, Moscow State University
What is BDII really?
OpenLDAP with LDBM backend
Three running servers with role rotation:
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One is updated every minute with a set of
processed ldapsearch results from any grid site.
One is used to serve the requests via a port
forwarding proxy
One is setteling down
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BDII users
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Primary users:
lfc-* utilities looking for storage elements
Resource Brokers updating grid information
cache
Some other grid utilities, but these are much
less popular then the first two.
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lfc utilities
Typcal query:
(GlueSEUniqueID=<se_name>)
(&(GlueServiceURI=*<hostname>*)
(GlueServiceType=srm_v1))
Results:
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Several rows for each query
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WMS cache update
Typcal query:
Results:
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(|(objectClass=gluevoview)
(|(objectClass=gluecesebind)
(|(objectClass=gluece)
(|(objectClass=gluecluster)
(objectClass=gluesubcluster)))))
Huge dump of grid resources, ~15-20 Mbytes.
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Testing method
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A number of parallel quering processes, with
synchronized start.
Each process runs a number of query sets in
a random sequence.
Results from each process are collected.
First implementation in perl using Net::LDAP
appeared to be amazingly slow and memoryhungry, so written in C with openldap-client
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SE search queries
There is almost no
dependence of the
response time from the
number of sequential
queries
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SE search queries (2)
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SE search queries (3)
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WMS queries
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WMS queries (2)
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Conclusion
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Seems to scale linearly. Just throw in more
CPUs?
High loads cause connection timeouts, but
our test show that „high load“ for a production
BDII means >1000 simulteneous queries!
Protocol and implementation are quite
inefficient. Network delay for the transfer of
WMS dump data is ~2 sec, so could be the
response time for the sequential same
queries.
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Conclusion (2)
Numbers for the modeling (next talk).
Net::LDAP is very slow.
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Acknowledgements
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The research was partially supported by
INTAS-CERN Grant 2005-7509
RFBR Grant 06-07-89199
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