What I believe (hypothesis) is happening with that 15% is that to prevent a yo-yo effect of cycling back and forth between allocated and unallocated.. and probable unnecessary churning of work... volumes that have grown and shrunk back down, use some algorithm so that the system will not reclaim 100% of that space, and instead keep a buffer as "reserved" for immediate growth. I believe this helps by avoiding excessively fragmenting the data, and keeping growth in large chunks of contiguous blocks.
_________________ Richard Siemers The views and opinions expressed are my own and do not necessarily reflect those of my employer.
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