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

On Wed, Dec 18, 2019 at 12:17 PM Mark Moseley <[email protected]> wrote:
>
> On Wed, Dec 18, 2019 at 12:40 AM Matus UHLAR - fantomas <[email protected]> wrote:
>>
>> >On Thu, Dec 5, 2019 at 10:00 AM Matus UHLAR - fantomas
>> ><[email protected]> wrote:
>> >> this could be issue of mod_delay, try using "DelayEngine off"
>>
>> On 17.12.19 09:56, Tony Stocker wrote:
>> >I implemented this statement and it did not change behavior.
>>
>> OK.
>>
>> >> Passive mode or port mode? Can be an ipv6 issue.
>> >
>> >Passive mode with a defined set of passive ports (64000-65000)
>>
>> that should be enough
>>
>> >> >The system in question is running CentOS 6.10 (Final) with the latest
>> >> >kernel, 2.6.32-754.24.3.el6.x86_64.
>> >>
>> >> quite old system. can be something with this system as long.
>> >
>> >System is still supported, doesn't EOL until next November. No issues
>> >with 1.3.5e, only with subsequent versions.
>>
>> Subsequent versions may require features not available in centos 6.
>>
>> >> can you try debugging? run proftpd interactively "proftpd -nd10"
>> >> and see the results..
>> >
>> >I've done this and ran the system for approximately ten (10) minutes
>> >capturing debug output. Should I sanitize and post it (it's
>> >approximately 10 MiB in size uncompressed)? Or is there something
>> >specific I should look for in the file and post?
>>
>> if you can find the exact places where the delays happened, logs from there
>> would be good. if not, you could turn on debugging with DebugLevel in config
>> and when anyone reports issues, look for logs from that time.
>>
>> Otherwise, I'm afraid nobody will dig through 10MiB file.
>>
>>
>
> Assuming your 'ps' output shows the IP address that an individual proftpd child is connected to (or get it from netstat), you could lsof+strace your own FTP connection. I.e. connect, fire up strace, and do a DIR or some other slow operation.
>
> That might give you some insight into what it's doing.

Okay I'll give that a try during our next test window. I'm assuming,
though want to make sure, that you intend for the lsof to be run on
the server end and not on the client end.

To address Matus' other point, we're going to set up a CentOS-8
server, as soon as we can free up the hardware, and install ProFTPD
1.3.6b (and 1.3.5e) on it and see if it has the same issues or not. If
not, then upgrading is what we'll do, but if it does have the same
issues then the problem resides with the ProFTPD code. Hopefully will
have that setup and working by mid-January for testing.

Thanks for the suggestions, both of you, I do appreciate the help.


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