TrueNAS External HDD problems

Discussions related to using VirtualBox on Mac OS X hosts.
mpack
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Re: TrueNAS External HDD problems

Post by mpack »

Solarczar wrote:Hmmm, something to remember, but I too was skeptical and will test as well.
Be sure to interpret the results correctly. A VDI consist of N x 1MB blocks (where N is the size of your drive in MB). The first time you write to a 1MB there may be a small write penalty for writing the block in such a way as to enlarge the file (not all hosts will have much of a penalty for this). With fixed you already payed all those penalties up front, with dynamic there is a one-time-only hit at the time a block is first written to. However, by definition there is a maximum of N hits in total, so do not read the results of testing as "I will always get this hit on writes".
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