Randomly slow network after transfer

Senor

Active Member
Jun 12, 2007
40
2
58
cPanel Access Level
Root Administrator
Hello -

I recently transferred a site off an old server and onto a new one. I'm having issues where the speed at which the server responds to web requests is sometimes quick and other times very slow.

I transferred from an old CentOS 6 box to a CentOS 7 install on a Hyper-V VM. The install and transfer went smoothly and everything is up and running, but the random slowness has got me stumped.

Some bullet points:

- CentOS 7
- Hyper-V VM
- Behind a NAT but the slowness is local as well
- Network seems to be fine -- no lost pings whatsoever
- VMQ has been disabled on both the physical NIC and the virtual switch created in Hyper-V
- Not database related as ALL pages show signs of random loading speeds


Odd things I've noticed
- No lost pings as mentioned above
- Local, passive FTP connections don't seem to work properly
- Local, active FTP connections work just fine
- Remote (i.e. through my firewall) passive and active FTP connections seem to be ok


I suspect this has to be an issue with the VM somehow as otherwise settings are identical to the old machine (other than WHM version and hardware specs).

I cannot for the life of me figure out why this is happening.

If anyone has any thoughts or suggestions, I'm all ears.

Thanks in advance.
 

Senor

Active Member
Jun 12, 2007
40
2
58
cPanel Access Level
Root Administrator
Further testing shows that, when the normal website (Apache-driven) is slow, the cPanel and WHM websites are working just fine and have no delays.

I'm not entirely sure what that means.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,917
2,248
363

Senor

Active Member
Jun 12, 2007
40
2
58
cPanel Access Level
Root Administrator
Hello @Senor,

I recommend using the traceroute utility to see if you notice any slowness/delay before the connection attempt reaches the individual server. We document how to use the traceroute utility on the link below:

How to Run the traceroute and ping Commands - cPanel Knowledge Base - cPanel Documentation

Thank you.
Hi @cPanelMichael -

Sorry, I should have mentioned that pings and a traceroute showed nothing out of the ordinary.

I'm experiencing less frequent freezing, but when it does happen, it happens for much much longer.

Again during these times, the cPanel/WHM sites load nice and quick. I still have SSH access, and have had to actually reboot my server several times to fix the freezing.

Additionally, top shows no processes hung, using excessive CPU or memory and there are no disk I/O issues.

I'm stumped.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,917
2,248
363
Hello @Senor,

Have you reached out to your server provider or data center to have them investigate to determine if there are any hardware issues leading to the slowness? That's generally the most common cause when everything else has been ruled out.

Thank you.
 

Senor

Active Member
Jun 12, 2007
40
2
58
cPanel Access Level
Root Administrator
Hello @Senor,

Have you reached out to your server provider or data center to have them investigate to determine if there are any hardware issues leading to the slowness? That's generally the most common cause when everything else has been ruled out.

Thank you.

@cPanelMichael

The server is in-house, so that would be me. :)

There are no (apparent) hardware issues or anything reported by any system checks.


Unrelated (perhaps?), but I had an issue last night where the server reverted to serving web pages from /var/www/html for requests made to its IP address, where previously it had served pages from the one domain I have on the server.

No changes were made at 4AM when this started.


I think I my server is either cursed and/or haunted. :(
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,917
2,248
363
Hello @Senor,

Feel free to open a support ticket and we can access the affected server to rule out any issues related to the cPanel & WHM software. You can post the ticket number here and we'll link this thread to it.

Thanks!