The document discusses different types of backends that can be used to store directory data in LDAP servers. It describes in-memory, LDIF, B-tree, MVCC, RDBMS, and NoSQL backends. Each backend has different performance, size, cost and reliability characteristics that make them suitable for different use cases like caching, tests, or storing very large directories.

1. A backend to tie them all ?

2. Emmanuel Lécharny
Apache Software Foundation member
Chairman of MINA project
PMC of Apache Directory Project
IKTEK Owner (www.iktek.com)
www.iktek@com, elecharny@iktek.com

3. What is the Backend anyway ?
Entries
+
Indexes

4. Entries/Index
dn: dc=example,dc=com
objectclass: top
objectclass: domain
dc: example
dn: cn=user1,dc=example,dc=com
objectClass: top
objectClass: person
cn: user1
sn: User one
dn: cn=user2,dc=example,dc=com
objectClass: top
objectClass: person
cn: user2
sn: User two

5. Criteria
Performance
Size
Cost
reliability

6. In Memory
Backend

7. In memory Backend
Internal data structures :
Btrees,
AVLs,
HashMap,
Lists,
...

8. In Memory Backend Usage
Cache
Ultra-fast server
No local storage
Tests

9. In Memory Backend
Performance
Size
Cost
reliability

10. LDIF
Backend

11. LDIF Backend
version: 1
dn: dc=example,dc=com
objectclass: top
objectclass: domain
dc: example
dn: cn=user1,dc=example,dc=com
objectClass: top
objectClass: person
cn: user1
sn: User one
dn: cn=user2,dc=example,dc=com
objectClass: top
objectClass: person
cn: user2
sn: User two

12. LDIF Backend Usage
Configuration
Schema
Tests

13. LDIF Backend
Performance
Size
Cost
reliability

14. BTree
Backend

15. BTree Backend

16. BTree Backend
Various possible
Implementations
Btree, B+tree, B*Tree, ...

17. BTree Backend
Average
Worst Case
Space
Search
O( n )
O( n )
O( log n ) O( log n )
Insert
O( log n ) O( log n )
Delete
O( log n ) O( log n )

18. BTree Backend
Usage :
Pretty much everything
Improvements :
Hashed keys
Cache

19. MVCC Backend
Performance
Size
Cost
reliability

20. MVCC
Backend

21. MVCC Backend

22. MVCC Backend
Usage :
Pretty much everything

23. MVCC Backend
Performance
Size
Cost
reliability

24. RDBMS
Backend

25. RDBMS Database

26. RDBMS Backend
Usage :
Existing DBAs...
ApacheDS experimentation :
Oracle Partition
http://svn.apache.org/viewvc/directory/apacheds/branches/ldif-partition/oracle-partition/?pathrev=982537

27. RDBMS Backend
Performance
Size
Cost
reliability

28. NoSQL
Backend

29. NoSQL Backend
Distributed Configuration Service
Distributed File System

30. NoSQL Backend
Usage :
Replicated backend
Huge base
ApacheDS experimentation :
http://www.stefan-seelmann.de/media/presentations/3rdOpenHUG2010_Seelmann_ApacheDirectoryHBase.pdf
http://svn.apache.org/repos/asf/directory/sandbox/seelmann/

31. NoSQL Backend
Performance
Size
Cost
reliability

32. Thanks!