Ok, so if you are forced to have several seperated deduplication pools, wouldn't it make sense to have the hashes syncronize in the background between all the DDB's? I would think CommVault would be working on this issue, because this is NOT a fix in my opinion.
1. This is a best practice which obviously Commvault and consultants will recommend. You are not forced to do this. Actually, I use 100 streams per MA/DDB and meet my backup Window so there is no need for me to follow this best practice. I would recommend starting small and growing only if needed. If you end up having bad performance, this is something to keep in mind and watch for.
2. It would make sens to share the hashes and I'm sure they are already working on a solution to this.
This work-around is going to force me to repurchase 5 top of the line media agents now, very, very costly! 100 grand unexpectedly is a lot of cost.
I'm sure you can get away with cheaper MAs than this. Also, the recommendation of 50 streams per DDB is only for the DDB, not the MA. If you have an insanely powerful MA, you could always have it host 2 or more DDBs. The important thing here is to keep each DDB on their dedicated spindles. Again though, if you already had 50 SSDs (just to go extreme here) for your single DDB, you could most likely split this in 5 and host all DDBs with your current hardware.
Also, this is something they NEED to teach in the admin/engineering classes, because both v8.0 and v9.0 classes with different teachers never mentioned this to us.
Unfortunately, like anything, some teachers are better than others. I remember this was mentionned to me when I had my course. There are other tweaks which I learned since then that wasn't talked about in the course. In the end, 5 days is not a lot to go through all the possible configurations of Simpana but I agree with you that the DDB paper should be one covered by the course.