Highly Available LDAP
If updates have been made to the LDAP namespace while the master LDAP server is down, the LDAP databases must be resynchronized prior to restarting the master server. There are two methods for doing this. If a service interruption is possible, the databases can be hand-copied after the LDAP server has been stopped. (Data files are kept by default in /usr/local/var.)
You also can use OpenLDAP replication to restore the database without the service interruption. First, start the LDAP server on the former master node as a slave. Then start slurpd on the current master. Changes received while the former master was out of service are pushed from the new master. Finally, stop the slave LDAP server on the former master node, and start Heartbeat. This results in a failback to the original configuration.
This article outlines a simple example of using open-source software to create some highly available basic network services. Network services including LDAP seldom require huge servers. The additional reliability provided by clustering and the duplication of servers and data files can increase overall service availability. The system worked under all tests, with a failover of less than 15 seconds in all cases. Given a good understanding of system loads and utilization, failover time could be reduced below this threshold.
Thanks to Alan Robertson, IBM Linux Technology Center, for his helpful comments and review.
The foregoing article is based on laboratory tests undertaken in a laboratory environment. Results in particular customer installations may vary based on a number of factors, including workload and configuration in each particular installation. Therefore, the above information is provided on an AS IS basis. The WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY DISCLAIMED. Use of this information is at user's sole risk.
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- Profiles and RC Files
- Understanding Ceph and Its Place in the Market
- Astronomy for KDE
- Git 2.9 Released
- OpenSwitch Finds a New Home
- Maru OS Brings Debian to Your Phone
- What's Our Next Fight?
- The Giant Zero, Part 0.x
- SoftMaker FreeOffice
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide