Difference between revisions of "OpenLDAP MDB vs HDB performance"

(Search time)
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=== Search time ===
 
=== Search time ===
This is the time to search the entire db via slapadd.  Note that with hdb, since it has to preload the cache, two times are given.  cold (Cache not loaded) and hot (cache loaded).  mdb never needs to preload the cache.
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This is the time to search the entire db via ldapaddadd.  Note that with hdb, since it has to preload the cache, two times are given.  cold (Cache not loaded) and hot (cache loaded).  mdb never needs to preload the cache.
 
  mdb: 0m1.435s
 
  mdb: 0m1.435s
 
  hdb cold: 0m5.304s
 
  hdb cold: 0m5.304s

Revision as of 23:47, 21 February 2013

Admin Article

Article Information

This article applies to the following ZCS versions.

ZCS 8.0 Article ZCS 8.0

Zimbra OpenLDAP Server

Performance differences between the mdb and hdb backends for OpenLDAP

Using real-world client data, I've compiled some brief performance differences between using the mdb and hdb backends to OpenLDAP with Zimbra. This particular client has 25,208 entries in their LDAP database. I dumped their accesslog and converted it to LDIF to give me a full weeks worth of real change data, and then ran that back against the database. This results in approximately 28,000 modifications performed against the DB.

Database load

This is the amount of time to load the database using slapadd -q

mdb: 0m11.237s
hdb: 0m38.727s

Advantage: MDB. It is 3.45 times faster loading the data than hdb.

Database size

Size of database on disk after slapadd completes. For hdb, this includes the hdb cache as well as db size. mdb has no cache.

mdb: 296MB
hdb: 627MB

Advantage: MDB. It is 2.11 times smaller than the hdb database.

Search time

This is the time to search the entire db via ldapaddadd. Note that with hdb, since it has to preload the cache, two times are given. cold (Cache not loaded) and hot (cache loaded). mdb never needs to preload the cache.

mdb: 0m1.435s
hdb cold: 0m5.304s
hdb hot: 0m3.103s

Advantage MDB. It is 2.16 times faster than hdb on the hot hdb search. Note that hdb performance degrades as the number of concurrent searches increases, while mdb performance is static.

Write performance

The following write performance was done with the 28,000 modification LDIF described above. It was done two ways -- Single node (no replication setup) and Master node (accesslog delta-sync database enabled). Time to do all 28,000 modifications is tracked. In the master node scenario, the size of the resulting accesslog DB is also compared.

Single node

mdb: 0m14.013s
hdb: 13m3.394s

Advantage: MDB. It is 55.90 times faster than hdb at performing 28,000 modifications.

Master node

mdb: 0m20.628s
hdb: 25m46.477s

Advantage: MDB. It is 74.97 times faster than hdb at performing 28,000 modifications.

Master node accesslog DB sizes

mdb: 100M
hdb: 234M

Advantage: MDB. It is 2.34 times smaller than the hdb accesslog DB.

Verified Against: ZCS 8.0 Date Created: 2/21/2013
Article ID: https://wiki.zimbra.com/index.php?title=OpenLDAP_MDB_vs_HDB_performance Date Modified: 2013-02-21



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