Fast Growth

A look at high-availability trends and directions.

A look at high-availability trends and directions.
Illustration by Randy Lyhus

The high-availability (HA) market is growing, and growing fast. HA is not only popular, it's necessary. An ongoing, organic growth trend in the HA arena has been developing for several years, fueled recently by the enhanced IBM System i Capacity BackUp Edition (CBU) offering. The HA market is on fire! If you're thinking about deploying an HA solution for the first time or enhancing your current HA environment, you're definitely not alone.

HA, for our purposes, applies generically to any multi-system resiliency solution, from basic disaster recovery to application resiliency. We define a disaster as an event that's recoverable from an off-site location only and has resulted from the unforeseen loss of a production server's computing capability due solely to forces beyond your control.

Macro Trends

HA macro trends follow two broad categories: those IT organizations that are moving to solutions that can provide real-time data protection, and those moving to solutions that can provide near-continuous application availability. The former tend to be small and mid-sized businesses that have been using tape backup deployments as their data-recovery solution but can no longer accept the corresponding recovery point objective (RPO). This trend is largely driven by a growing intolerance to data loss and by compliance requirements in certain industries. These businesses see deficiencies in the tape backup method as the primary data-recovery approach. A tape backup method yields a recovery point equal to that of the last save, which could be hours or even days. The restored image is a point-in-time backup, which means intervening data changes are gone and may not be recoverable. This fact has led increasing numbers of customers to implement solutions that continuously replicate production data to a backup system, often at a remote location (see Figure 1).

The second broad category are those IT organizations that do continuous data replication to a backup system but are under increasing pressure to meet ever-tightening recovery time objectives (RTOs). RTO is the time it takes to recover a critical application to full production capability after some kind of outage. Organizations that have deployed a full-blown HA environment regularly switch their workloads to alternate servers. They run their production on the alternate servers for an extended time until the next scheduled switchover (or switchback, if you like). These clients represent best practices and are well prepared for outages.

An extension of this demographic is that set of IT organizations that need both a rigorous RTO capability and a disaster-recovery capability. These clients often have two systems deployed in the datacenter (or campus) to achieve the best possible RTO, plus a third system deployed at a remote location to address disaster-recovery requirements (see Figure 2). Many of these clients are moving toward independent auxiliary storage pools (IASPs). IASP-based solutions, such as cross-site mirroring (XSM) or the Copy Services for System i Toolkit, protect datacenter operations while using a logical-replication solution to support disaster-recovery requirements.

Mike Snyder was a senior technical staff member in System i development at IBM.

Steve Finnes is the System i Business Continuity product manager with IBM. Steve can be reached at

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