<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/xhtml; charset=utf-8">
</head>
<body>
<div style="font-family:sans-serif"><div style="white-space:normal">
<p dir="auto">On 21 Oct 2020, at 13:56, Steven M. Bellovin wrote:</p>
</div>
<div style="white-space:normal"><blockquote style="border-left:2px solid #777; color:#777; margin:0 0 5px; padding-left:5px"><p dir="auto">I've had to disable Time Machine backups of the directories<br>
containing my IMAP messages—I was getting at most two<br>
backups per day because each one took so long. Some of<br>
it, I'm sure, is because I have about a million messages, but I don't think that that's the whole story—my backup laptop, which has most of those messages but does not normally<br>
run MailMate except periodically when I want it to catch up, can handle Time Machine reasonably well.<br>
<br>
The issue, then, would seem to be something about messages<br>
being added to or deleted from some mail folders, possibly<br>
propagating up the directory tree. Is that right? Is there some organizational pattern I could use that would cut the time?<br>
Is it, for example, that I have too many messages in certain folders?</p>
</blockquote></div>
<div style="white-space:normal">
<p dir="auto">I exclude ~/Library/Application Support/MailMate/Database.noindex from my Time Machine backups. It makes a real difference (measured using <em>BackupLoupe 2</em>).</p>
<p dir="auto">I’m pretty sure the database index files can (and should) be reconstructed after a file recovery. These database files get pretty large (mine total to about 600MB for 49,000 messages). Each of the many index files covers <em>all</em> the messages in the system, and each can be updated after any message is received, moved or expunged. As a result, Time Machine records a fair amount of this database (around 500MB for me) on every backup cycle.</p>
<p dir="auto">In contrast, the message contents are stored as single files under ~/Library/Application Support/MailMate/Messages.noindex. Time Machine uses storage proportional to the size of the messages that change during each backup cycle.</p>
<p dir="auto">Glenn P. Parker<br>
<a href="mailto:glenn.parker@comcast.net" style="color:#3983C4">glenn.parker@comcast.net</a></p>
</div>
</div>
</body>
</html>