Martin: Side effects of SSD usage to considerDate: Nov 21, 2013
The performance boost offered by solid-state drives (SSDs) doesn't happen in a vacuum. SSD usage can have some unanticipated side effects, according to Dennis Martin, president of Demartek. "If you start to deploy SSDs on a wide basis, you might have to reconsider your physical-to-virtual ratio -- how many [virtual machines] VMs you put in a box," he said.
One side effect is higher utilization of CPUs, Martin said. In one Demartek test, he said, CPU usage went from 10% to 50% due to the faster storage offered by SSDs. "Part of that depends on how much RAM you can get and how many cores you have. So, if you're putting SSDs in those boxes, depending on how hard the apps are working, you might have to rethink that, because now the SSDs will significantly improve turnaround time, which means CPU [usage] is going to go up if those apps are busy."
Another side effect is the impact on an environment's network. Martin said his firm conducts numerous tests with SSDs, and in one case, they measured the efficiency of servers equipped with hard drives versus solid-state drives. But the tests didn't reveal a significant improvement with SSDs until they swapped out Gigabit Ethernet network equipment for 10 Gigabit Ethernet (GbE) upgrades. Once that change was made, "performance went through the roof" with SSD, he said.
Martin said that high-speed networks such as 10 GbE and 8 Gbps and 16 Gbps Fibre Channel can take advantage of solid-state's performance. "They weren't built this way, but they were really made for SSDs," said Martin. "SSDs and high speed [networks] just go together."