When Telecom Xtra started looking for a new email system last year, it took the opportunity to look at its storage system as well. The ISP ended up moving from an environment of 100% direct-attached storage (DAS) to 50:50 between DAS and a storage area network.
The country’s biggest ISP now has 1.8TB each on Sun servers and an EMC SAN, with a tape-based backup silo and Veritas software for management. Storage needs are growing at a rate of 30% year on year and Xtra needs a highly available environment that can be rapidly repaired. Its mail environment is second only to the access network in terms of criticality to the business, says IT director Shane Ohlin.
The system was implemented last August and it’s probably time to talk again to storage vendors and find out what their strategies are, he says.
“There’s talk that standards bodies will find ways to get different suppliers to play together in the sandpit. We would love to be able to take different storage technologies and plug them together in a way that works, but at the moment we manage that complexity by having very few suppliers.”
In choosing a storage solution, what mattered to Xtra was whether it would do the job, deliver the robustness needed and be able to recover from any type of failure.
“We had some challenges with the old mail system. With one of the last outages we knew what had gone wrong straight away and were able to fix it, but we still had to go through the long drawn-out process of reloading.”
Ohlin says having a SAN means time to recover is vastly superior. “We have a triple mirroring installation. Every mailbox is effectively stored three times. We disconnect the third mirror and back it up daily, but we could do it two or three times a day if we saw the need. It’s an expensive way to go, but if the worst happened our recovery times would be measured in hours rather than 15 to 20 hours plus.”
Ohlin says the storage strategy has to be aligned with business needs.
“For us spending a million on the SAN was well worth it because of the criticalness of mail. For some areas of business it wouldn’t have been so important. Also from a purely economic view, the SAN is an environment that is growing rapidly but the more gigabytes of storage you add, the lower the overall cost. So if you’re storage needs are fairly static it might not be so compelling.”