Features such as automated storage tiering and storage domains on today’s enterprise storage arrays go a long way toward making it feasible for organizations to successfully host multiple applications with different performance and priority requirements on a single array. However prioritizing the order in which data and I/Os are tiered is an entirely differently matter as organizations typically want the data and I/Os associated with their mission and business critical I/Os serviced ahead of lower priority applications. This is where the Quality of Service (QoS) Plus feature found on the Oracle FS1 comes into play as it does more than provide the “brains” behind its auto-tiering feature. It also re-prioritizes and re-orders application I/O according to each application’s business value to the enterprise.
Historical Treatment of Application I/O by Storage Arrays
Storage arrays by default treat incoming read and write I/Os from all applications the same (Figures 1 and 2 below.) Whether I/Os are issued by an Oracle Database or an application retrieving archival data, storage arrays ingest these I/Os in the order in which they arrive and then process and reply to them in the same order.
Conventional Storage Arrays’ “First-In-First-Out” I/O Input
The issue that this “First-In-First-Out” process potentially creates in consolidated environments is that I/O from an application doing archiving is handled in the same manner as I/O from an OLTP application trying to access an Oracle Database. This puts I/O processing out of alignment with business priorities.
Conventional Storage Arrays’ “First-In-First-Out” I/O Output
Oracle FS1 Realigns Application I/O with Business Priorities
The Oracle FS1’s QoS Plus addresses this misalignment between available technical resources and business priorities with Application Profiles that have Archive, Low, Medium, High and Premium priorities. Enterprises may use pre-tuned and tested Application Profiles for Oracle Database and key Oracle and third-party applications that come with the Oracle FS1 to expedite storage provisioning with just one click or create their own. These profiles are associated with each application accessing the FS1 and serve two purposes:
- Data associated with each application is placed on the tier or tiers of storage associated with its FS1 application profile.
- Read and write I/Os from each application are then ingested and prioritized according to its application profile to create a “Priority-In-Priority-Out” means of handling I/O.
Using Priority-In-Priority-Out, the FS1 services I/Os associated with the highest priority applications first and then services I/Os from other, lower priority apps according to how they are categorized on the FS1. As Figure 3 illustrates, I/Os still come into the FS1 the same way as before – the order in which they were sent.
FS1’s “Priority-In-Priority-Out” I/O Input
The difference is that the FS1 recognizes each application’s respective I/O, correlates it to its profile and then responds to each application I/O based upon how it is prioritized as Figure 4 below illustrates.
FS1’s “Priority-In-Priority-Out” I/O Output
The Oracle FS1’s “Priority-In-Priority-Out” component of its QoS Plus feature gives enterprises more flexibility to mix and match applications of different priorities on the same FS1 array or within FS1 Storage Domains without worrying about how I/O from low priority applications will affect their Premium or High Priority applications. QoS Plus ensures that I/Os from Premium and High priority applications are serviced before I/Os from lower priority applications. However it also ensures that I/Os from lower priority applications are queued up so that their I/Os are serviced in a timely manner to meet their respective service level agreements (SLAs).