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Daniel Richards
New Pleskian
In recent days we've come across a new issue involving painfully slow Plesk Advisor, and an inability to use the Plesk Update function. We have found the trigger for this behaviour, which doesn't appear to be documented yet by Plesk.
This is on Plesk Onyx 17.8 update 38 on dedicated servers in OVH data centres
We looked at this article:
Plesk Installer and Advisor extension are working slow
and this is not relevant to the issue we face - there is no problem with nameserver resolution speed, and the query
returns in 0.0102 seconds, so well below the 1 second the article is looking for.
We have eventually traced the issue back to OVH and their DDOS mitigation service. We had set the DDOS mitigation provided by OVH to 'Permanent' as opposed to the default of 'automatic' It is meant to only add an extra 30-50ms to each query as they get analysed under their DDOS protection system, and for this particular usecase - we thought we would benefit from this being permenantly active instead of risking a delay following a DDOS attack while the automated system kicks in. It's not meant or expected to cause any other problems other than a 30-50ms delay on each query.
The problem with Plesk Advisor is resolved when the OVH DDOS protection system is restored to 'automatic' and therefore inactive unless it detects an attack underway.
We don't yet understand why this occurs as other aspects of the server, including network throughtput work just as expected. The only issue we can find between plesk and OVH DDOS protection system seems to be with advisor and update/upgrade in plesk.
We have found the same now on an unrelated plesk 17.8 setup on a different OVH server in a different datacentre in a different region, so this is unlikley to be an isolated problem for Plesk and OVH customers if DDOS mitigation is active.
I wanted to put this here, so if anyone else with this issue uses OVH servers- they can see this extra potential cause to consider - so hopefully avoid the many hours that has gone into tracking this issue this far.
This is on Plesk Onyx 17.8 update 38 on dedicated servers in OVH data centres
We looked at this article:
Plesk Installer and Advisor extension are working slow
and this is not relevant to the issue we face - there is no problem with nameserver resolution speed, and the query
Code:
/usr/local/psa/admin/bin/php -f '/usr/local/psa/admin/plib/api-cli/settings.php' -- '-g' 'password_strength'We have eventually traced the issue back to OVH and their DDOS mitigation service. We had set the DDOS mitigation provided by OVH to 'Permanent' as opposed to the default of 'automatic' It is meant to only add an extra 30-50ms to each query as they get analysed under their DDOS protection system, and for this particular usecase - we thought we would benefit from this being permenantly active instead of risking a delay following a DDOS attack while the automated system kicks in. It's not meant or expected to cause any other problems other than a 30-50ms delay on each query.
The problem with Plesk Advisor is resolved when the OVH DDOS protection system is restored to 'automatic' and therefore inactive unless it detects an attack underway.
We don't yet understand why this occurs as other aspects of the server, including network throughtput work just as expected. The only issue we can find between plesk and OVH DDOS protection system seems to be with advisor and update/upgrade in plesk.
We have found the same now on an unrelated plesk 17.8 setup on a different OVH server in a different datacentre in a different region, so this is unlikley to be an isolated problem for Plesk and OVH customers if DDOS mitigation is active.
I wanted to put this here, so if anyone else with this issue uses OVH servers- they can see this extra potential cause to consider - so hopefully avoid the many hours that has gone into tracking this issue this far.
