Issue Plesk slowed down to become unusable

[kongo09]

I'm running Plesk 18.0.41 on a virtual server with Ubuntu 20.04.3 LTS.

The system hosts four domains with next to no traffic, mostly does some email forwarding (less than 1 GB per month) and runs a (mostly idle) nextcloud instance.

Everything used to be speedy and fast, but since one week, the system became really unresponsive, especially Plesk itself. These are the symptoms:

• Login as Plesk admin works but it takes minutes to change from one view to the next and often it times out, e.g. with a 504 Gateway Time-out of nginx
• Mails don't get delivered anymore as servers trying to connect receive a time-out
• The webserver responds and nextcloud is accessible
• I can ssh and the system doesn't really look too busy. This is the output from top:

Tasks: 92 gesamt, 1 laufend, 90 schlafend, 0 gestoppt, 1 Zombie %CPU(s): 0,2 be, 1,2 sy, 0,0 ni, 98,6 un, 0,0 wa, 0,0 hi, 0,0 si, 0,0 st MiB Spch : 8192,0 gesamt, 5506,1 frei, 821,7 belegt, 1864,3 Puff/Cache MiB Swap: 0,0 gesamt, 0,0 frei, 0,0 belegt. 7248,8 verfü Spch

I haven't really changed anything a week ago and the whole system used to be very snappy and responsive. Any suggestion where I start looking?

 

[LinqLOL]

Are you sure your resolving (/etc/resolv.conf) nameservers are ok? Sounds something networkish.

 

[kongo09]

/etc/resolv.conf is generated automatically. It contains three nameservers. I tried some queries on them and they all work as expected.

I noticed one (maybe related, maybe not?) thing:

• When accessing the Plesk admin pages, the browser makes calls to firehose.us-west-2.amazonaws.com. I have no idea what that is. The address resolves fine but it takes very, very long to get an answer from aws. As a user, it looks like Plesk is not loading, but it is actually the call to AWS that is blocking.

Any ideas around that? Could that be the cause?

 

[mow]

Add 127.0.0.1 firehose.us-west-2.amazonaws.com to your local /etc/host or %WINDIR%\System32\drivers\etc\hosts and check what happens.

 

[kongo09]

Hm, before I found time to test it, it picked up on speed again. This is confusing.