The Windows client has been stuck on version 3.3 (yes, bizarrely no third dot field in the version) for over 2 years now, despite fresh dates being claimed on the download pages for 3.3.1-3.3.6. For example, if I download the "9th July 2014" Windows client 3.3 from the 3.3.6 download page, checking the datestamps inside the zip show that setup.exe was created on 1st March 2012.
I suspect the vast majority of Linux Amanda server installations involve one or more Windows client boxes (even if it's just one for Windows filestore/printing/Active Directory to support Windows desktops). This means that the Windows client needs to be relatively robust and any important bugs fixed in a timely manner, which sadly isn't the case at the moment.
Example issues with the Windows client include:
* Regular crashing of ZWCService regularly and not coming back up even with automatic restart (e.g. 3 crashes in a row).
* Doesn't stop when the backup finishes and continues to write large files to the client filestore that aren't tidied up.
* Seems to occasionally timeout - sometimes successfully retrying, but more often the retries fail too (this has never happened on Linux clients).
* Writes in ZIP64 format, which the Linux Amanda server can't partially extract from (yes, you have to extract the entire backup and then transfer it to Windows to use the PKWare Zip Reader [7-Zip won't even handle it!]).
* Backup speeds from the Windows clients seem to be about half the speed of Linux clients (yes, network speeds and hardware speeds were roughly the same).
* "estimate client" (and possibly "estimate calcsize" too) seems to be extremely slow on Windows clients compared to Linux clients. I had to use "estimate server" instead.
All of this makes me suspect that a) the Windows codebase is quite different from the Linux one (I never have any trouble at all with Linux clients) and b) whoever is maintaining that Windows codebase has left the project and it's been abandoned.
It would be nice if someone from Zmanda would officially comment on whether Windows is even a platform beinng actively supported - over 2 years with unfixed serious issues for the Windows client really does detract from the Amanda project as a whole and it's starting to make Amanda look very poor as a backup solution in a heterogenous environment.
Of course, for all I know, these Windows client issues have been fixed in the Enterprise version, but with free "rivals" like Bacula around, I'm more likely to switch to that than pay high fees to go to the Enterprise version.