[MlMt] Dealing with MailMate disk usage

[Bill Cole]

On 24 Feb 2021, at 11:05, Raza Rizvi wrote:

> Hi,
>
> One of the nice things about MailMate is the great search options and 
> instant response, but that comes at the price of having a local copy 
> of your email, and no doubt many of you have multiple mailboxes, as I 
> do.
>
> So on my 250GB SSD root volume I have just about 50GB now used by 
> MailMate and I am fast running out of disk space. So I thought since 
> “/Users/xxx/Library/Application Support/MailMate/Messages” is an 
> alias pointing at the mail store of “/Users/xxx/Library/Application 
> Support/MailMate/Messages.noindex” this would not be a problem. I 
> could just copy the mail store to a different external SSD and have a 
> new alias to it (called Messages).
>
> Some hours later, having made the copy (and deleted the original 
> because of the afore mentioned lack of space), I restarted MailMate. 
> It bombed.
>
> Copy the files back to the “Users/xxx/Library/Application 
> Support/MailMate folder, recreate the original alias, no problems and 
> MailMate starts up.

I believe that you need to make that change within MailMate rather than 
try to construct the linkage yourself. See 
Preferences->General->Messages Folder.

> Anyone have any suggestions why this did not work?

That has to be answered by Benny to get the definitive truth.

However, one possibility is that you created the "alias" in a manner 
that MM does not expect. MacOS supports a complex "alias" which is 
robust enough to survive moving both the alias and its target because it 
contains low-level file ID information. There is also a cross-platform 
(i.e. POSIX-defined) file type called a "symbolic link" or "symlink" 
which MacOS supports *and which the Finder displays just like a MacOS 
alias.* By definition, symlinks are less robust, simply being a pathname 
(absolute or relative) in a file labeled by the filesystem as a symlink. 
MailMate's ~Library/Application Support/MailMate/Messages object is a 
symlink with an absolute pathname, NOT a MacOS alias, but the Finder 
cannot show you that difference and it also cannot create a symlink, 
only an alias. Because MailMate expects a symlink there, it probably 
uses the POSIX-standard readlink() function to get the real pathname to 
the real Messages directory, and because MM creates that symlink it 
probably does not handle the case of readlink() failing because it is 
called on a regular file (that MacOS knows is an alias) instead of on a 
symlink.

BUT: that is just a theory. You could test it by creating a symlink to 
the physical location of the Messages directory (instead of an alias) in 
a Terminal session:

     ln -sf  '/Volumes/OtherDisk/path/to/real/Messages' 
'/Users/<username>/Library/Application Support/MailMate/Messages'


-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire