Homebrew

[Daniel J. Luke]

On May 18, 2010, at 9:10 AM, Ryan Schmidt wrote:
> I don't use Time Machine; I don't know if this problem actually occurs. I thought I remembered someone saying on the list some time ago that it did.

Our users often say things that are only partially correct ;-)

I would want to test this before saying that it was actually a problem.

>> The advantage being that a TM backup will take up a little less space (and be a little less broken when restored). The disadvantage being that it will re-expose all of the old bugs we saw in individual ports when we used symlinks.
> 
> Again, I wasn't suggesting we change MacPorts to go back to using symlinks instead of hard links.

Ok, I thought you were advocating at least testing it again.

> Andrea asked a general purpose question about the difference between symlinks and hard links, and your response made it sound like there was no reason to ever use symlinks, that they had no advantage at all.

I was replying in the context of MacPorts image mode (since as a project, we've tried it before and it had problems that were fixed by switching to hard links).

> I was pointing out a case where they do, and that in fact, it's hard links, not symlinks, that are the peculiar/unusual entity to me; it would never occur to me to create a hard link (I would use a symlink, or if necessary a Mac OS alias). Even after using MacPorts for years and experiencing firsthand that its hard links do what they do just fine, hard links still feel strange to me. They don't fit neatly into my view of how filesystems work which was formed by years of experience on Systems 6, 7, 8, & 9.

There are a lot of things that are different in Mac OS X ;-) 

> Another problem with hard links is one that was discussed on a MacPorts list not long ago, about determining how much space the MacPorts prefix takes up. Both the "du" command and the Finder's Get Info window can't tell hard links from real files and misreport the size of the prefix by counting the hardlinked items twice. Symlinks wouldn't have this problem.

Have you verified this?

The manpage for du says: "Files having multiple hard links are counted (and displayed) a single time per du execution. Directories having multiple hard links (typically Time Machine backups) are counted a single time per du execution."

--
Daniel J. Luke                                                                   
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