File compare "resource size"

[SimonMac]

Transferring everything from my old to new NAS, using the OS X App "Folder Compare" and it's showing differences between source and destination file "resource size", any idea what this means?

Using rsync with the switches -arvz to copy the files if that's useful info

Thanks in advance

[eek]

What disk format do the old and new disks have?

Resource fork - Wikipedia, the free encyclopedia will give you a clue as to what is happening. I reckon you'll have a lot of hidden .appledouble folders

[Contreras]

Different cluster sizes?

E.g. Disk A has 4KB clusters, Disk B has 64KB clusters.

A 128KB file would need either 32*4KB clusters (128KB used) or 2*64KB clusters (128KB used), no slack space and the disk usage is identical.

Increase that file by 1-byte and now it needs either 33*4KB clusters (132KB used) or 3*64KB clusters (192KB used), Disk B uses 60KB more space to store the same file.

Best not to use file size to verify the copy. If that's what you want 'md5sum' or similar would be the appropriate tool.

[Sysman]

Transferring everything from my old to new NAS, using the OS X App "Folder Compare" and it's showing differences between source and destination file "resource size", any idea what this means?

Didn't you mention you had Gemini for OS X?

I've been using that to compare source and destination files as I transfer them to my NAS.

And optionally zapping the originals to free up space there, which Gemini can do for you.

[SimonMac]

Didn't you mention you had Gemini for OS X?

I've been using that to compare source and destination files as I transfer them to my NAS.

And optionally zapping the originals to free up space there, which Gemini can do for you.

Gemini only shows duplicates in the same folder, unless I am mistaken?!

[unixman]

Files can occupy slightly different sizes on disk, but still contain identical data. Try comparing checksums on the "differing" files.

[Sysman]

Gemini only shows duplicates in the same folder, unless I am mistaken?!

Heck no. You can lob more than one directory at it, add multiple file selections, keep on adding stuff and then give it the go ahead to do its stuff.

It also understands the iPhoto library and will move stuff to iPhoto's trash if you tell it to. It shows stuff in Aperture libraries too, but (probably quite sensibly) refuses to alter those. Dunno about the iTunes library, I haven't tried it with that.

What I've been doing is transferring my stuff to my NAS via rsync, but carrying on editing stuff on the Mac. Then I chuck both the source directories on the Mac and the target directories on the NAS at Gemini and let it sort them out. Once I've deleted all the duplicates from the Mac (I also have copious backups of this stuff), any files that are left will be ones that I've edited since I did the rsync transfer.

Once Gemini has produced its results, there's another hidden feature which is really quite nifty: Right click on one of the folders in the bottom pane and you can choose "Select all duplicates from folder XXX" and it will tick all the relevant boxes for you.

The only grouse I have with Gemini is that it the easiest way to do all this is via drag and drop from Finder into Gemini but the Gemini window likes to sit in the middle of the screen and you have to keep moving it off to one side.