~written by Michael Moore, Dataram Storage Blog Team Member
Anyone who has engaged in the storage industry has certainly been challenged in many ways. We have all chased the elusive “perfect” solution; each of us has heard conflicting conclusions as to what that means. Many times all the ideas will work – that makes the decision even harder. But what if it mostly works, or kind of solves the problem? What if you have two or more viable answers to your needs?
More common than not, I/Os are slowly building in your network, slow-down is happening and you do not even know it. Let’s blame it on slow drives, software, processors, old technology, etc. Maybe it is none of these.
Let’s lightly explore the “in-flight” issues that come up when I/O bottlenecks arise. Your network is doing its job and all is well. Does the slow-down just show up? No – it sneaks in. The intangible and elusive I/O bottleneck never announces itself. It is not a bulk arrival, it grows fractionally. There is no alarm or warning – it just happens. We all understand this and can write our own chapter to this story, right?
What next? We all know what’s next—network slow-down complaints come in. Eventually the drama of some person thinking they need to reboot server, and so on. The pressure comes. No one planned for this, no budget line item for it, white boards cannot fix it and traditional solutions are patches, but – hope is at the door – a hardware manufacturer shows up. The perfect solution is here, ALL new hardware! Oh yeah, don’t forget your checkbook, it is hundreds of thousands of dollars. Add disk—$$ cha-ching! Make them fast SSDs—BIG $$$ CHA-CHING! Well maybe we can just do a software optimization? Great idea, but does that really fix the problem? Well maybe add more cache! That will work!
OK, let’s buy what we need! So we need cache for each host, right? We need it for the new ones and the old ones. You are ahead of me now, why put new money into old. Not to mention you might be maxed out already, maybe additional cache will not be enough. Then you have spent more money and, to top it off, it only works for the server in which it is installed.
Let me add one more bit of indigestion. Now you have servers, different configurations, with different maintenance schedules, different build dates, etc. Get the picture? A new time management program depicts at least one man-hour a week to manage the boxes, or the net is over five man-days per year.
Now let’s ask the question this way. Can we get I/O enhancements which meet the following criteria?
- No hardware configuration change
- No additional maintenance charges from the server manufacturer
- No downtime
- Ability to remote- and local-manage
- Improve both reads and writes
- Do not add more disks
ANSWER – Yes, and with less risk than any other solution with immediate benefit.
Here is how – put one HA pair of XcelaSANs into your fibre SAN. No intrusion on your current network. 256GB of TRUE DRAM cache servicing your reads and writes.
Noted storage commentator David F. Bacon said it best – “As a result, the high-speed cache memory that acts as a buffer between main memory and the CPU is an increasingly significant factor in overall performance. In fact, upgrading your cache may give you more of a performance boost than upgrading your processor.”