Making Time Machine work with the ReadyNAS

btaroli wrote:

odysseus wrote: ... it creates a journaled HFS+ *case sensitive* file system. What are the implications of using a .sparebundle file with a presumably case-insensitive file system instead of a case-sensitive one for Time Machine? ... There may be implications. What this depends upon is how the filesystem of your Mac(s) is configured. If you, for example, back up a Mac with a case-sensitive filesystem to a TimeMachine volume that is case-insensitive, then this can result in situations where files with different names (file vs fiLe) overwrite each other. So, from a TimeMachine perspective it is always safer to use case-sensitive filesystems. There have been other threads discussing this issue. Do some searching. :) In my case, I always use case-sensitive filesystems. It just avoids any confusion or sloppy behavior.

Hey folks,

I find the whole "case-sensitive (journaled) filesystem on a sparsebundle" aspect quite intriguing as well. Mostly because (as has been noted since 2 years ago): that's what Time Machine seems to *favor*... initially on sparseimages, and then later with sparsebundles. And —on the surface anyway— that fact seems to go against the grain of *non*case-sensitive filesystems, to which the OS (and 3rd-party apps) have defaulted for almost a decade now. Back in that "OLD" thread, i found posts by schalliol and m_stoll (as well as btaroli, toad and pjc) most interesting. [i had intended to use links there, but url tags seem to be prohibited?]

Anyway, i'm not posting to get any deeper into that puzzle... i just wanted to share a little tidbit i discovered. The man page for hdiutil has what i assume are typos in the -fs section. (i'm still on 10.5.8, but the online man page for Snowy shows the same error):

 -fs filesystem
where filesystem is one of HFS+, HFS+J (JHFS+), HFSX, JHFS+X, MS-DOS, or UDF. 

It really bugged me that all of the blogs, articles, hints, threads, etc., all had to spell out "Case-sensitive Journaled HFS+" in qoutes on the command line (or script). Where (or what) is the corresponding acronym? [must be one since Time Machine/Capsule always use them.]

I tried that "JHFS+X" there, but it failed with:

Finishing…
DIHLDiskImageCreate() returned 22
hdiutil: create: returning 22
hdiutil: create failed - Invalid argument

So did HFSX+J and JHFSX. But i hit gold on my 4th attempt though...

/usr/bin/hdiutil create -verbose -size 96g -type SPARSEBUNDLE \
-fs HFSXJ -volname 'Backup of iMacG5' ./iMacG5_0011243d60c9

I've checked that with hdiutil imageinfo and diskutil info (and verifyVolume) and Finder. It's right: HFSXJ is indeed the proper shortname for "Case-sensitive Journaled HFS+", and apparently it's fully undocumented (or mis-documented perhaps).

I thought maybe at least btaroli might get a kick out of that. [and it may turn out that Apple always uses case-sensitive sparsebundles with Time Machine/Capsule for special reasons as yet unknown to us... because it sure seems odd otherwise.]

-HI-