Hardware High Availability & Bandwidth Configuration

March 3, 2016 High Availability Blog Articles, Networking Blog Articles

Hardware High Availability (HA) and logical replication are both smart choices when deciding how to design your company’s backup IT environment. Each solution acts differently, and there are many factors to consider when choosing between the two. One of these factors for hardware HA is bandwidth.

Hardware HA

Hardware HA is either a disk-based replication that works at the TotalStorage SAN level, or a page-replication solution at the OS level. It requires switchable independent auxiliary storage pool (IASP) technology, which is where local journaling of all objects takes places to support recovery after a failure. This technology designates part of the disk unit for various object storage, mitigating the risk of disk failure.

Hardware HA and Bandwidth

Hardware HA uses two different functions to handle bandwidth.

When a change is made to memory pages and being written back to disk, Geographic Mirror transfers the changes to the target system. When a page has a significant number of changes locked in memory, memory page-based writes have the advantage. This is because regardless of how much data changes, the entire page will be sent to the target system. Geographic Mirror uses Data Port Services to efficiently handle the transferring data with up to four communication lines in parallel.

Metro Mirror and Global Mirror each take data sectors that change on the source SAN external storage unit and copies them to a corresponding sector on a target SAN unit. For IBM i operating systems (OS), each memory page that is written to disk will conclude with the changed sectors being written. IBM TotalStorage bandwidth between SAN units is granular. This allows for additional fiber-channel cards to increase the amount of connections, and then meet your company’s bandwidth requirements.

Hardware HA and Disaster Recovery

Hardware HA also has disaster recovery (DR) solutions associated with these functions. This happens when along with the transfer of user data to the target IASP, the local journal receivers are replicated to the IASP to support recovery in the event of a failure. Metro and Global Mirror can also be used together to create a second copy of your company’s data. The technologies use Metro Mirror for the first copy, and Global Mirror to create a second copy from the first.

For further information about how different HA technologies can impact your bandwidth and recovery after a disaster, contact Baseline Data Services at (317) 707-3941 today. Our knowledgeable engineers will help you design a solution that is best for your company’s IT environment and business continuity.



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