I'm trying to back up a directory to a fat32 usb external hard drive. My rsync keeps throwing errors that it can't do a chown on any of the files on the fat32 usb drive. I just want it to copy the files, no permissions since fat32 doesn't allow for permissions. What rsync switches should I use? I'm using r a v now. Thanks!

At a glance, I'd suggest removing the -a argument. That's what's probably causing the errors. As you noted, FAT doesn't allow for permissions such as ownership etc.., so you need to copy the stuff while IGNORING the permissions.

See the rsync man page for more details.

I thought I needed to use the -a since I'm archiving to an external drive?

You can still use the "r" ( recursive) or "t" ( maintain the files last modified time) option. Definitely do not use the "a" option (keep group & user ownership) as Ggirl rightly said.

Ok I'm trying it now with -r. Never used -t before. If I don't use -t will it change the modified time to right now, then make subsequent rsyncs take longer because it thinks they're different files?

Sounds reasonable, but I personally am not certain HOW rsync determines whether a file is the same or not. mtime seems a good candidate though.

Something you might consider for all this, especially for in the event that you wish to RESTORE any of this backup at some time to its original location and state more easily, would be to reformat your FAT drive to something more befitting the sort of backup that you are sending to it.

Is there anything preventing you from reformatting the backup drive to an Ext* filesystem, or some filesystem that supports the permissions required?

The permissions are of no importance to me. The files are only on this Linux server because it was the only one that had enough space to copy them all to originally.

I need to be able to move the drive possibly back and forth between Windows, Mac, and Linux machines, and I think only FAT32 will go between them all without issue?

Does anyone else know for sure if I should or shouldn't use the -t to make future rsync's go quicker?

I'm pretty sure Macs can read NTFS, as can linux. Ext3 can be read with ext2ifs, a utility for windows; there's probably a utility for the Mac too.

Edit: yep, just checked google, ext2ifs anf ntfs-3g run on Macs too.

Thanks. wouldn't using ntfs preserve some set of permissions, which could cause problems as i move the external drive back and forth between computers on different workgroups and domains?

I suppose you could have problems with permissions, but I haven't really had any. You could always chown/chgrp the files as needed.

Well I have it running now in verbose mode, and it keeps throwing a bunch of mkstemp failed no such file or directory (2) and mkdir failed no space left on drive (28).

I know before I started the rsync there was a hundreds of GBs of space on the external drive, and my data set i'm trying to copy is around 200GB, so there's plenty of room. Any idea what these errors are about? Or should I maybe open a new post with a new subject?

Actually for the mkstemp errors, its showing the real filenames with a . then random letters after it, assuming rsync writes a temp file with the extra stuff at the end, then removed the extra stuff after it writes successfully.

removing the -a got rid of it, closing thread.