Often, when faced with a tightening budgets, we try to make more use of what we already have. Tell someone they are only using 10 percent of their brain, and they immediatelybelieve you; but tell them they are only using 30 percent of their storage, and they ask for a whitepaper,magazine article, or clarification on how that percentage is calculated. I actually visiteda customer that was only using6 percent of the storage attached to their Windows servers!
So, to help those of you making data center resolutions to stay on budget, the terms to remember are "Reduce", "Reuse" and "Recycle".
- When people come to request storage, are they being reasonable about what they need today, or are they asking for what they might need over the next three years? They might need 50GB, but they ask for 100GB, in case they grow, and a year later, you find they have only 15GB of data on it. On the flipside, the person asks for what they need but some storage admins give out more, just so they don't have to be bothered so often when growth happens. Finally, I have seen this formalized into fixed size LUNs, all the disk is carved into big huge 100GB pieces, so if you need 20GB, here's one big enough with plenty of room to grow.
If you are going to keep on a budget, remember that storage today is 30% more expensive than storage next year. That is the average drop in both disk and tape on a dollar-per-MB basis. If there is any way to postpone giving out storage until it is actually needed, you can save a bundle of money. Timing is everything! In the event of a disaster, getting immediate replacement for disk can be very expensive, but if you can wait just two weeks, you can negotiate a better deal. I thought of this while going to the movie theatre yesterday. A "hot dog" and a bottle of water was $8.00, but if you are able to wait two hours and eat after the movie, you can get a much better meal for less.
- A lot of companies buy new storage because their existing storage isn't fast enough, or doesn't have the latest copy services. This can easily be solved with an IBM SAN Volume Controller (SVC). The SVC can virtualize slower, functionless storage, and present to your application hosts virtual disks that are faster, and with all the latest disk-to-disk copy services like FlashCopy, Metro Mirror, and Global Mirror.
Chances are, you have unused disk capacity spread across all your storage today, but perhaps they are formatted into small LUNs. The SVC can combine the capacity, and let you carve up big LUNs at the sizes you need.This is like taking all those tiny pieces of soap in your shower and forming a new bar of soap, or taking all the crumbs at the bottom of your bread box, and making a new slice of bread. And, the virtual LUNs are dynamically expandable,so give out only the amount they need today, as it is simple to expand them to larger sizes later.
- Of my 13 patents, the first will always be my favorite, on a function called "RECYCLE" for the Data Facility Storage Management Subsystem Hierarchical Storage Manager (DFSMShsm) product, which is now a component of the IBM z/OS operating system. Basically, tapes could contain hundreds or thousands of files, such as backup versions or archive copies, and these expired on different dates. As a result, a tape would be written100 percent full, and then over time, decrease in valid data to 80, 60, 40, 20 until it hit 0 percent. In some cases, a single filecould hold an entire tape hostage. RECYCLE was able to read the valid data off tapes that were perhaps less than 20 percent full, and consolidate them onto fewer tapes. As a result, a whole bunch of tapes could be returned to the scratch pool, and reused immediately for other workloads. This also helps in moving to newer, higher capacity cartridges, such as the new 700GB cartridge that IBM co-developed with FujiFilm.(This RECYCLE function exists in our IBM Tivoli Storage Manager software, as well as our Virtual Tape Server, but is called "reclamation" instead, to avoid confusion on searches.)
When evaluating your use of tape, determine if you are making best use of the tapes you have now, and perhaps a RECYCLE (or reclamation) scheme may be in order. Fewer tapes can save money in many ways, such as reduced storage costs, and reduced courier costs to send the tapes offsite. Tape media can still be 10-20 times less expensive than disk, based on full capacity.