I thought I was done with TSM. And just when you think you are out, they pull you back in.
Only in this case I am being pulled back in by some feedback from a colleague on my previous column. I didnt want to relegate his input to a comment where it wouldn't get adequate notice, so I am reproducing it here in full and unedited. Full credit for this goes to Mario Correia. Mario has some impeccable credentials as a TSM administrator and consultant, and worked with one of the most respected TSM services groups in the industry. Mario had some great feedback on how often to run TSM reclamation on a Data Domain device.
"You really hit all the points with TSM and DD but I disagree on the comment about more aggressive reclamation at the 20%-30% thresholds.
Typically, 50% is the magic number where you hit the point of diminishing returns. If a tape is 50% utilized, I can take two volumes and consolidate onto one. I still have a net gain of 1 volume. But, once I go beyond that point, I’m not really saving anything from a volume perspective plus I’m also working much harder to get that minimal savings. When you throw in the actual space savings post-dedupe, it’s even less.