Re: Abysmally poor write performance

[Michael Donnelly <donnelly@sendmail.com>]

> > Using RedHat 8's OpenLDAP 2.0.25, I have populated an LDAP directory
> > with 200 entries.  The total size of all gdbm files is about 1500kb. 
> > Each user (entry) has 7 objectClasses: top, person,
> > organizationalPerson, inetOrgPerson, posixAccount, shadowAccount,
> > qmailUser.  slapd is configured to maintain these indices:
> >
> > index   objectClass,uid,uidNumber,gidNumber,memberUid   eq
> > index   cn,mail,surname,givenname,mailAlternateAddress eq,subinitial
> >
> > The system is a 1GHz P3 with 256M of RAM and SCSI disks (it is a Dell
> > server).  Updating a single entry with GQ can take up to 5 seconds to
> > write.  I just now wrote a script to update gidNumber on the 200 entries
> > using ldapmodify(1), and it took 5 minutes 9 seconds.
> >    
Some other things you can do to increase performance for writes:

1) Mount the openldap-ldbm directory with the -noatime flag.
2) Mount the openldap-ldbm directory from a RAID array
3) After reading the slapd.conf manpage for gotchas, set the ldbm option 
"dbsync 15"
4) all of the above.