Based on my experiences with upgrading 5.6 to 6.0, no. It's not avoidable. If you have checked its disk partitioning before with 5.6 then checked it again after the upgrade (diag hard device disk), you must have noticed the log disk was split to three partitions. It was one or two before. We don't use WAN optimization or even local disk logging, but it had to happen.
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