Re: [Proftpd-user] Exceptional slowness and lost connectio ns 1.3.6b vs 1.3.5e

> We've been using 1.3.5e for a long time without issue. However when we
> attempted to shift to 1.3.6b many of our users are suddenly unable to
> complete their authentications and timing out, and those that can get
> that far encounter exceptionally long lags on doing simple 'dir/ls'
> commands, on the order of 2-4 minutes to get returns. These problems
> cease as soon as we fail back to 1.3.5e, so it is not something with
> our network or firewalls.
> 
> The configuration file used is the same one, it's not two different
> identical files, it is literally the same file. Other than sanitizing
> it for IP addresses and names (and pulling out comments) it is posted
> below.
...

One of the largest culprits for slower directory listings -- especially for "wider" (flat, with many thousands of files) directories, was only recently fixed, and I haven't had time to do releases with the fix yet:

  https://github.com/proftpd/proftpd/issues/863

Many FTP users use graphical FTP clients, which do a directory listing after authentication, thus such users often report "slow login", even though the issue may more accurately be "slow directory listing".

If you're able to test the latest 1.3.6 branch (or master), you might see if the slowness is gone for you.  Alternatively, in your 1.3.6b configuration, you might try using:

  FSCachePolicy off

which disables the caching of stat(2)/lstat(2) filesystem results -- whose inefficient implementation is causing the latency.  (The current code uses a much simpler and more efficient means of caching that same data, without the latency penalty.)

Hope this helps,
TJ


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