All-Flash Right Type
Any addition of flash storage will result in a performance boost over disks. The key is to find the right type, amount and location of flash storage. Here's how to make flash a cost-effective investment instead of simply throwing hardware at a problem.
It is no coincidence that as storage prices fall and drive capacities increase, companies are finding new uses for these larger disk drives. With the cost of commodity-class disk drives falling to pennies per gigabyte, even small to mid-size companies can afford to build multi-terabyte data storage environments that would have been the envy of spy agencies just 20 years ago.
But massive storage systems come at a cost -- performance, reliability, and management. It is one thing to throw massive hard disks at a database in order to meet capacity requirements but quite another to optimize that database so that your users get the performance they need. Today solid state storage, commonly called flash, is meeting that need. But as with rotating storage, not all flash storage is the same; so just throwing a flash array in front of a database might not provide the results one expects.
Selecting the right type of flash storage can make the difference based on the applications being run, says John Flisher, technical consultant manager for Mt. Pleasant, SC-based eGroup Inc. If a company is heavily transaction oriented, such as a retailer or financial services provider, then users are more likely to be doing write activities rather than reads. Similarly, a company that does a lot of read operations where the data is relatively static would benefit from flash that is optimized to cache read data.
There are three types of storage environments: all disk, hybrid disk and flash, and all flash. A move to all flash could be prohibitively expensive and likely would not produce benefits that match the cost, he says. A hybrid environment could significantly improve the performance of the storage environment with a return on investment that the chief financial officer or board of directors will understand without delving into techno-speak.
Before a company spends a dime on changing its infrastructure, it needs to identify the types of applications it runs and where performance bottlenecks exist. While the industry's "general rule of thumb" is to recommend 5-10 percent flash being used to front-end disk storage, he says, without fully understanding your applications means you might be spending too much money and receiving too few benefits in return. First a company needs to determine if it wants flash memory or if it needs flash, says founder and chief analyst with Minneapolis-based StorageIO. If an analysis of the applications shows the company needs flash, it becomes much easier to budget for the extra expense, he says. The return on investment (ROI) for solid-state storage should be three to six months, he says.
For example, let's say an on-line retailer is looking to speed up transactions. If flash that is optimized for write operations could save, for example, 10 seconds per transaction for a company that does 2,000 transactions per day, the company will save the equivalent of 5.6 hours per day of productivity as compared to a database that has no flash front-end. If the company's average employee is earning $30 per hour, that 5.6 hours per day is $168 per day. Over a standard 40-hour work week per year, that's a savings of nearly $22,000 in the first six months alone. Oracle has a useful total cost of ownership calculator that compares flash to disk storage. Remember that these are just estimates; as the saying goes, your mileage may vary. "If the conversation turns to cost-per-gigabyte or terabyte of storage, it's the wrong conversation," Schulz says. Flisher agrees that looking at the cost of flash storage alone should not be the deciding factor on whether or not to add it to your storage infrastructure. Often applications need a little boost in performance in order to translate into significant gains in productivity.