Duncan McCallum, Velobit CEO, responded to my post about shared versus direct attached storage and referred readers to one of their guides on the same subject. Clarity about the strengths of both approaches is useful and merits even more discussion to help organizations make the best choices for their budget and application requirements.
The truth is that we actually agree on many points. We agree that you can enhance the capabilities of a server-side SSD solution with additional software and hardware. That can get you performance and other benefits but it also adds complexity and potentially more points of failure especially when you add more servers into the mix. You still have to maintain and tune your existing array to work well with your server. Plus, growing your solution by adding servers also means more software and more complexity. All of these extras add capital and operational costs — and still may not have all the high availability (HA) features that an array may have such as RAID. Don’t forget that HA affects costs. When you lose an SSD in your server, you have downtime. A Kaminario K2 requires minimal operating cost – the same as a server solution.
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