Why are customers Not using JBOD for Exchange deployments ???
Microsoft started recommending JBOD for Exchange deployment since Exchange 2007, with every new version the IOPS requirement for Disk subsystem is going down.
With this, the investments on Exchange messaging system can be optimized. However, lot customers are still not opting JBOD as their sub systems. A lot of times, I have faced this question from the customers “ Why adoption of JBOD for Exchange is lower than expected”. As per my experience and opinion.
Following are the major aspects; not going for JBOD.
1) Using Existing SAN: Most of the customers have existing storage infrastructure. They want to leverage the same expertise and infrastructure for the messaging system and Do not want to increase the administrative overhead of the existing team.
2) Expectations: Customers must expect more likely exchange database failovers; due to disks failures. This will increase more tasks to Exchange administrators. As they have to keep re–seeding of the databases. However, the customer should keep in mind that, this is helping to optimize their deployment cost without causing any downtimes for the messaging system. As we expect to have 3 database copies.
3) Disk selection: Customers going for JBOD should select the disk cautiously. It is highly recommended to use Enterprise class JBOD Vs Consumer class disks. Most of the design ignore these recommendations.
Enterprise-class HDDs must provide maximum performance under a 100 percent duty cycle and continuous Input/Output (I/O) workload in a high-vibration environment. While some have used the term Mean Time Between Failures (MTBF) to express the length of HDD life in general, a more meaningful benchmark, the Annual Failure Rate (AFR), better defines the estimated life of an HDD in a continuous, high workload environment. The AFR is the relation, expressed as a percentage, between the MTBF and the number of hours that the device is expected to run per year (100 percent duty cycle = 8760 hours per year). For example, you can calculate the AFR for an enterprise HDD with an MTBF of 1,200,000 hours as follows:1,200,000 hours/8760 hours = 136.9863 years, then (1 failure/136.9863 years) x 100% = AFR of 0.73%
Moreover, customers should choose disk connections based on the requirements.