The good people at Computer Economics have recently published an article entitled Storage Management Disciplines are Declining. Which is the best thing I’ve heard all week. Unless your job title includes the words “Storage Manager”.

Unused Capacity: Horrors!
CE has looked at data center benchmarks for disk capacity utilization and percent of capacity accessed within the last 15 days over the last decade and found “. . . by both of these measures, disk storage management practices have declined over the past decade, in mainframe, UNIX, and Windows server environments.”

Here are some stats about mainframes, which were all that is available on the freebie version on their website. I think it safe to assume the trends are worse for the lower-cost systems. I’m in touch with CE, so maybe I’ll be able to get more detailed info into a future post.

Mainframe Average 1997 2006
Installed MIPS 575 2028
Installed Disk 2.2 TB 11.6 TB
Allocated Disk 68.5% 61.3%
Unused Disk 0.7 TB 4.5 TB
Disk Accessed in Past 15 Days 78.8% 72.6%

Unix & Windows Capacity Allocation

UNIX Windows
Local Attach 56.6% 46.6%
SAN Attach 75.5% 55.8%

Fuel Tank Management Practices Decline
The storage management hairball has always puzzled me. Why do we manage storage? Because it is a precious resource, right? But prices have been dropping like a rock for decades, so why is it precious? Enterprises everywhere are happy to invest in personal and server resources whose utilization ranges from ~3% (PCs) to ~20% (servers). So why does storage need to be at 60-70%?

You don’t spend a lot of time worrying about how much fuel is in your car’s tank. When it gets “low” – however you define that – you fill it up. Storage systems are the inverse: when they get “too full” you add capacity or archive. When I was a starving student, I managed my fuel tank pretty closely to conserve cash. And now that gas is $3 a gallon, I’m more thoughtful about it again. But storage capacity is as cheap as its ever been and getting cheaper. So why do we have to manage it? The one good argument is that since prices are dropping so fast you can save a lot of money by delaying purchases. On the other hand you are spending a lot of money to manage what should be a cheap resource. Why?

Problem or Opportunity?
The fuel tank analogy is instructive. Unlike adding gas to a car, adding capacity to a SAN or an array is an involved process. You have no choice but to “manage” the storage and risk your data. Compare that to ZFS, which has implemented storage pools, so new disks are automatically added to the available capacity. Google’s GFS has a similar capability.

Continuing the automotive analogy: one of my first cars had a manual choke. Chokes control a carburetor’s fuel-air ratio for starting the car when the engine is cold. You had to remember to reduce the choke as the engine warmed up or else you’d be burning a lot of gas and gunking up the engine. Manual chokes got replaced with automatic chokes that had bi-metallic coils that would control the choke plate. They’d usually work but could stick, so you’d be burning a lot of gas and gunking up the engine and not even know it. The solution: get rid of the carburetor – a mechanical analog computer – and replace it with fuel injection.

Storage Injection: It’s What The Big Boys Use
Right now we are using expensive people and expensive software to manage cheap disks wrapped in expensive cabinets and controllers. Rather than an automatic choke, why don’t we go to fuel injection, i.e. storage pooling?

Net Net
This decline in storage management is good news. It demonstrates that as storage prices decline, practitioners are making the rational economic decision to exchange capex for opex: investing more in hardware and less in management.

Memo To Storage Titans
To: Storage Titans
First thing this morning: wake up, smell coffee, change course. What this research says is that if you make storage cheaper and easier to use, people will buy and “waste” a lot more of it, just as they do with PC CPU cycles. Someone is going to be the Toyota of next-gen storage. Why not you?

Comments welcome, of course.