A recent post on the dumb disk fallacy argues that enterprise storage isn’t overpriced. That misses the point: enterprise arrays may not be overpriced – but they overshoot most market requirements.
That’s why there’s so much innovation in the high capacity/low cost end of the market. And why high-end monolithic arrays are the mainframes of tomorrow.
Disk drives are only 5-10% of an array’s cost. Since dual-parity arrays protect against 2 drive failure/read errors, the logical question is “why not just replicate the data 3x for 15-30% of the array’s cost and get better protection?”
Comparing bare drive costs to array costs isn’t realistic. Power supplies, chassis, cabinets, processors, interfaces and firmware all cost money.
Servers have it all
Which is why I prefer to look at server costs – especially servers with lots of disk slots. Like a Supermicro Superchassis 846E1-R710B 4U 24-bay storage server.
For $5500 you get:
- A 4U storage 24-drive chassis w/ redundant power & cooling, 2 GigE ports
- Mobo with dual quad-core Xeon 2.5 GHz processors and 16 GB ECC RAM
- 24 1 TB 7200 rpm SATA drives
- Dual 12 channel PCIx RAID cards
- Support for 15k SAS drives if desired
Update: Some folks asked where that pricing came from. It is from Priority Computer & Networks. I have no experience with them, but I like the nifty online configurator. End update.
The drives are 40% of the configuration’s cost. And I’m sure you could do better. Throw Linux or OpenSolaris storage stacks on the box for free, or, for example, Nexenta’s Enterprise Gold Edition for another $4k and you’ve got a nifty NAS/iSCSI array.
Buy several and layer HP’s IBRIX or ParaScale software on them and you’ve got a scalable file cluster with redundancy and performance for way less than monolithic enterprise arrays. Or even mid-range modular arrays.
When are enterprise arrays better?
Enterprise arrays aren’t designed to compete with Supermicro boxes and FOSS. They offer benefits way beyond commodity-based storage – but at a price.
- Performance. Big redundant write caches are perfect for transactional apps – but the corner cases make engineering them a nightmare.
- Scale-up architectures. Embedded switches, star networks, high-performance FPGA controllers, FC and Infiniband – all the hot-rod, go-fast, low-volume tech give big arrays a scale-up capability that enterprise IT likes – until its gone.
- Bullet-proof hardware and software. Years of tweaks to the exception-handling and careful drive qual and firmware control makes these systems more reliable.
- Layered software. Database and email backup, LAN and WAN replication and all the other options give enterprise IT a warm feeling and operational flexibility.
So what’s the problem?
On the Supermicro the storage is $0.50/GB, while on the enterprise array it’s $5 GB or more. And enterprises can’t afford that for everything.
As intuition suggests and recent research confirms data is getting cooler. We store more and more and access it less and less.
Translation: we need cheap capacity, not high performance. And as Google proved years ago, just because it’s cheap doesn’t mean it is slow.
The StorageMojo take
I don’t know if enterprise arrays are “overpriced” – if people buy ’em, how bad can they be? – but I am confident that they overshoot the performance requirements of most applications by a wide margin. And that performance is very expensive.
But enterprise IT learned long ago that it is better to be overconfigured than to be caught short. And in good times who cares?
But times aren’t good and despite the Q3 numbers we haven’t seen the end of the Great Recession. The good old days aren’t coming back.
The point behind comparing array prices to dumb disks is to remind people that there might be a better way to achieve their goals than spending $4.75 per GB on performance that most of their data doesn’t need.
If it is redundancy you’re after there are better alternatives than RAID 6. With the arrival next year of pNFS and the commoditization of 10GigE we have many more options for high performance at a low cost per GB than ever before.
Courteous comments welcome, of course. I once worked for Sun and have done work for IBRIX and Parascale.