We all know about the importance of location in real estate. What's the equivalent in storage? Performance. It's the one thing that you can't fix. When you look at storage, it should be what you look at first, second, and last.
Location and Performance
The three most important things in real estate are location, location and location. Real estate agents may talk about the attractive paint job, the great landscaping and the new roof. But if you didn't like them, you can fix them. The one thing you can't fix? The house's location.That's why it gets the top three slots.
What about storage? You'd never know it from storage vendors, but the three most important things in storage are performance, performance and performance. You can fix most everything else with server-based software. You need replication? Your database can do it all by itself. You think thin provisioning is great? It's cheaper and better to get it with a VM. But performance? You want that go-cart to do 100 mph ... uphill??? Fuhhgeddahbouddit, buddy. However fast you're going is as fast as you're going to go.
The Storage Performance Problem
We know there's a performance problem because of the fundamentals of spinning disks. We know there's a problem because vendors are coming out with expensive solutions that emphasize performance, and companies are going public based on storage performance; oddly enough, in the case of Fusion IO, they don't even deliver real storage, just a board that goes into a server! But people are so desperate for performance, they try it anyway. One company has even come out with an affordable solution that just screams performance.
The biggest thing that convinces me there's a problem comes from the leader in server consolidation and virtualization, VMware. I went through their best practices in configuring virtual storage, which tells you all you need to know. They have four best practices. All four best practices amount to the same thing: make sure you get enough performance from your storage! Their best practices are explicit: you should buy storage not based on capacity, but on performance.
Here they are:
- Configure and size storage resources for optimal I/O performance first, then for storage capacity. --> Don't buy TB, buy iops (i/o's per second).
- Aggregate application I/O requirements for the environment and size them accordingly. --> When you buy iops, make sure you look at all your applications.
- Base your storage choices on your I/O workload. --> In case you didn't get it yet, pick storage based on iops!
- Remember that pooling storage resources increases utilization and simplifies management, but can lead to contention. --> Remember that using a classic SAN can make storage performance worse, so don't be fooled.
According to VMware, there are four most important factors in storage: performance, performance, performance, and performance!
Does anything but performance matter?
Of course it does. Do you want to lose your data when a server fails? You'd better not buy server-based storage. Do you want your performance to drop to a crawl when there's a disk fault? You'd better ask how frequently that happens, how badly RAID re-builds impact performance, and for how long (hours of severely degraded performance taking place weekly is not unusual in a large system). But performance still takes the top 3 slots. It's just like location: if there are two equally-well-located houses, you avoid the shack with the outhouse and buy the comfortable, modern house. With storage, if you have two systems with enough performance to meet your current and future needs, you pick the one that isn't a board stuck in a server, and the one that has enough affordable capacity.
Performance is more important, by far, than any of those silly features the SAN vendors love to rattle on about. But in a post-SAN world, performance is front and center. The bigger disks get, the worse performance gets. The more you virtualize and consolidate your servers, the more performance you need. In a word, you need SSD's, because they're fast storage. But they're expensive. So an appropriate blend of SSD's and spinning disks would be great, fast but affordable, if they really were in a seamless pool of storage. That's the Xio Hybrid ISE in a nutshell. In a performance-starved world, it's food for the hungry -- food you can actually afford to buy.