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Re: Abysmally poor write performance

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.