Migrating a Synology NAS to a UniFi UNAS Pro 8 with Robocopy, SMB Multichannel
The author moved their Synology NAS contents to a Ubiquiti UniFi UNAS Pro 8, expecting a straightforward process. Both devices support SMB and the author had a fast internal network, but the migration turned into an educational experience. The author recalled writing about Robocopy being better than XCopy for moving large numbers of files in 2007.
They initially used Explorer, but encountered errors with filenames containing special characters. Switching to Robocopy helped identify the issue, which turned out to be the presence of alternate data streams (ADS) in NTFS files. Robocopy's /X switch skips ADS, so the author added this option to their command. The migration initially had inconsistent performance, with file transfer rates fluctuating.
The author tried various thread counts and options but found that disabling /Z (Robocopy's restartable mode) improved copy performance. They now recommend using Robocopy without /Z for LAN migrations, reserving /Z only when specifically needed for its restartability feature.
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