If you are zipping up a bunch of files and transmitting the zip to a backup target, unbuffered is the way to go. So there is a tradeoff, but which is appropriate for you depends on your particular case. Large files tend to be less frequently accessed in practice than smaller files. You probably don't need to buffer anyway.Reads and write of large file data blocks increase the probability of requiring disk I/O.
Large file blocks don't tend to stay in the cache for very long anyway, unless you have a ton of memory relative to the file size. The performance penalty with buffered I/O is substantially worse for large files. The usage note mentions large files vis-à-vis buffered I/O because: The operating system takes care of synchronizing file writes back to disk, and reads can be pulled directly from memory. Buffered I/O incurs a performance penalty the first time the file is accessed because it has to copy the file into memory however, because memory access is faster than disk access, subsequent file access should be faster. Buffered I/O augments the simple copy to optimize for future reads of (and writes to) the same file by copying the file into the filesystem cache, which is a region of virtual memory. Speaking of little speed tweaks, you can also use this PowerShell command in a shortcut as a convenient way to toggle Windows Defender real-time scanning off & on (e.g.Unbuffered I/O is a simple file copy from a source location to a destination location. While great for LARGE files like VHDs and VMDKs, for most other files, it will just add time to the copy operation so we took it out. You might also remember the /z option that allows files to be restarted in the middle of a transfer interruption and wonder why it was omitted. It’s been a while since I had to scrounge up these switches so having them all in one spot for next time will be useful for me. r:1 /w:0 – Retry once and wait zero seconds. mt – MultiThreaded – 8 threads is the default. copyall – copies over all NTFS permissions (be sure to run under elevated permissions)
log – creates a log file of all files copied e – grabs all empty directories of course.
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