data directions: V4R3’s New Storage Management Systems
IBM’s recent announcements on the AS/400 included the availability of new facilities to store and retrieve your data, in particular your non-current transaction and reporting data. Just what does that mean?
The AS/400 is one of the best, if not the best, systems for business transaction processing. It loves to take orders, manage inventory, cut checks and do all the other day-to-day data related activities that we do all the time. However, it has never been stellar at storing the large amounts of data that we keep as a result of these activities. Oh, it kept the data OK, but at a pretty high cost both in terms of performance and in disk storage costs.
Even with the advent of cheaper disk units, more efficient RAID technology and faster tape drives, it is still expensive to keep all this data. Has anyone ever installed a system and never added more disk, or wished they had a faster tape drive?
With the new announcements, IBM has added some very nice capabilities. Some of these have been around for a while but have been enhanced. Others have been added because of customer demands. All can be used to increase performance by limiting the transaction database, while at the same time giving you quicker access to historical data stored in a variety of methods.
There are three major portions of this announcement that help with storage management.
- Backup Recovery and Media Services (BRMS)
- Hierarchical storage management (HSM)
- Integrated hardware disk compression
Besides the hardware technology of these enhancements there are new facilities to train the system to do much of the grunt tasks for you. Setting up system and object policies for storage does this. These policies are the software rules that are used to tell the system which of the methods you want to use, and when to apply them.
The BRMS owns the job of managing your backups and the media you use. This is key if you have lots of tapes for various objects and data stores. Through policies you define, the system will back up to the correct media, keep track of that media and request you to put that media on the system if you need that data back.
HSM is the overall owner of data policies on the system. It manages if the data is kept on disk, compressed or on tape. Integrated hardware disk compression is another way to keep data in a smaller footprint. Yep, that’s right, just like on your PC (hopefully without the headaches). Even if you have to keep the data around for access or reporting, you can compress all those spaces and duplicates out of it. IBM estimates anywhere from two to four times size reduction using their compression algorithm. When the system needs the data, it de-compresses it as it brings it to memory. The really neat feature of this is that the compression and de-compression takes place on the disk controller, not the main system processor. So even if you have a single processor, the controller takes the workload to increase performance.
This should not be used for your daily transaction files because of the performance impacts, but it could be great for the month-end, quarter-end and year-end files. Or if you have to restore an archive from tape for the auditors, you may want to put it in a compressed ASP so that it does not impact you too much.
Another good use of this is for reports that you want to keep available online, but out of the way. Spool files take up a tremendous amount of room on the system. Compressing them reduces that need, yet still leaves the spool files around if you need them.
Another advance is the use of the tape archival units (part of BRMS). This is mostly for very large organizations and can be very useful for them.
Objects can be stored on tape, the system keeps track of the tape it is on (with the save(*KEEP) option) and then when needed, the system will automatically get the tape and put it in the drive for you. For this you do need the automated tape library. The *KEEP option saves the data object, but keeps the header on the system to keep track of it.
Additionally, you could use a COLD device for storage. This gives you the ability to keep lots of data on a CD-ROM for reports, invoices, history data and other data in a non-volatile format. If you cannot find policies that you like, there are a number of APIs that are available for you to build your own facilities. Expect tool software vendors to come out with some of their own variations soon.
With V4R3, IBM has brought lots of enhancements to help those of you who are always pressed for storage and availability of data. With the system policies, you can have the system manage much of this for you automatically.
What more could you want?
John Bussert is president of Swift Technologies (Marengo, Ill.), a company specializing in AS/400 and Windows NT software. firstname.lastname@example.org