As with all things, YMMV, but I have had success moving from VTS/VSM to DASD. It was hard to quantify cost savings, because the vendor didn't separate out cost of the virtual box (including its DASD) from the cost of the robotic library.
Some important factors, in my opinion: 1. Do you have DASD you can get for "free"? In my case, I had a DS8100 with excess capacity so I could set up volumes for TMM (Tape Mount Management) without purchasing new DASD. It's not really free, of course, but acquisition cost for this project was zero. 2. Understanding the tape data and usage: I used a combination of MXG and IBM's Volume Mount Analyzer, and found out that 80% of the tape datasets were 40MB or less, making them 'low hanging fruit'. 3. Having a good working relationship with the application/end-user people you're going to affect. In my case, it was very important with one office (because of some ancient history between our two organizations) that I agree to be on-call to fix problems with their batch workload if TMM caused something to blow up. After about a month, everything was working smoothly enough that we were able to change all the rest of their tape over to TMM. 4. System-determined BLKSIZE: I was surprised at how many tape DD statements did NOT use it. We corrected some even before moving the dataset to DASD, just for the perforance impact. 5. SMS compression: while it can cost some CPU, it can minimize the space you need to accomplish the move to DASD. There's possibly a trade-off point somewhere - not yet analyzed - in the small dataset range where there's no point compressing the dataset because the decompression time might outweigh the I/O time. 6. Hierarchical Storage Management: Good understanding of how you will use HSM/ABR to migrate the TMM data to ML2. If you don't want to migrate, then plan to buy new DASD regularly as you keep accountant-mandated 20 years of detailed transactions around on disk. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
