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CPU High wait

D

dicko_md

Basic Pleskian
Hi

I have 2 servers that are built from the same template. Server 1 runs great apart from the odd high on the apache memory but server 2 has a high CPU wait IO which is constantly about 60%.

What could be causing this ?

I have run a fsck on the server 2 and rebooted at 2am and this brought the cpu wait IO down to well under 10% like my server 1 but by 4am the CPU shot back up to 60%

Does have anyone have an idea what could be causing this and if not what I could check ?

Ive done lots of top and top c but I am quite new to linux so still learning.

Everything else is also running OK as far as I can see but then again the Plesk 11.5.30 #35 is saying its all OK on the Health Monitior but if I leave it and it gets higher the websites load even slower.

serverb_high_cpu.png

Thanks in advance.

Martyn
 
Hi,

is this a physical or virtual server?

If it's a physical server, have you check your harddrive and also the settings are identical on both machines?
Maybe AHCI enabled on Server2?

Regards,
Kristian
 
Hi

Sorry. Its a virtual server.

Like I said it was OK from about 2.30am to about 4am and went back up to 60% cpu and then I found this below......could I have been hacked as Ive just found this in the error log in httpd or is this actually working ?

[Mon Mar 10 03:14:50 2014] [error] [client 220.133.247.121] File does not exist: /var/www/vhosts/default/htdocs/phpTest
[Mon Mar 10 03:14:51 2014] [error] [client 220.133.247.121] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 03:14:52 2014] [error] [client 220.133.247.121] File does not exist: /var/www/vhosts/default/htdocs/pma
[Mon Mar 10 03:14:52 2014] [error] [client 220.133.247.121] File does not exist: /var/www/vhosts/default/htdocs/myadmin
[Mon Mar 10 04:38:08 2014] [error] [client 209.126.230.76] File does not exist: /var/www/vhosts/default/htdocs/robots.txt
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/w00tw00t.at.blackhats.romanian.anti-sec:)
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/scripts
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/w00tw00t.at.blackhats.romanian.anti-sec:)
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/scripts
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/db
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/dbadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/admin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/myadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysql
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/db
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/dbadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysqladmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/typo3
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/myadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysql
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysqladmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/typo3
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin1
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin2
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/pma
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/web
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin1
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/xampp
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin2
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/pma
[Mon Mar 10 04:43:39 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/web
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/web
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/xampp
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/websql
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/web
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/websql
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5-pl1
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5-pl1
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysqladmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Mar 10 04:43:40 2014] [error] [client 62.210.132.69] File does not exist: /var/www/vhosts/default/htdocs/mysqladmin
Click to expand...
 
Hi,

this does not look like you've been hacked, these are "normal" scans on the net in these days.

If it's a virtual server, what makes you sure it's related to your virtual server and not some other virtual server on the same node?
Maybe some other virtual server on the node is creating backups in that time frame?

Try monitoring your I/O with htop. If nothing pops up, it's most probably a problem on the node.

Regards,
Kristian
 
@KristianM

It is possible to see "Health Monitior" in "Power User view" Interface? I can find this statistic only in "Service Provider view". I'm not a reseller, so the best view for me is "Power User view".
 
Hi

Thats a relief.

Ive installed htop now.

apache usr/sbin/httpd is showing up a lot and using about 2.5% of memory

processor/cpu 1 and 2 is averaging under 2%
memory is about 1GB out of 3.5GB
swap file is 0 of 2GB
load is between 4.5 and 5.6 on all 3 figures
218 tasks and only 1 or 2 running

Hope this helps

Martyn


Thanks

martyn
 
Azurel said:
@KristianM

It is possible to see "Health Monitior" in "Power User view" Interface? I can find this statistic only in "Service Provider view". I'm not a reseller, so the best view for me is "Power User view".
Click to expand...

Hi Azurel,

as fair as I know the Health Monitor is not available in Power User Mode.
I wouldn't trust it anyway. I got so much false information from it that I uninstalled it :)

Regards,
Kristian
 
cpu_usage_server2.png

This graph shows that I rebooted the server about 2.30am but by about 4am the wait IO went up again from well under 10% to 60% wait IO

Martyn
 
Hi dicko_md,

my guess is that it's Node related.
You can try and ask your provider to move server2 to another Node or to the same node as server1?

Regards,
Kristian
 
Hi

Thats great I will ask tomorrow. Should I say anything specific to them if they ask why ?

Is that a simple thing that wont involve down time ?

Thanks again

Martyn
 
Hi Martyn,

well you should ask your provider to check I/O performance on the node.
He most probably won't just move you without any reason.

If there is a downtime or not depends on how your provider migrates and what kind of virtualisation is used.
Your provider will be the best to ask in this regard.

Regards,
Kristian
 
I Spoke to my server provider today and both servers are on the same node but he was Ok to move if I really wanted to.

He suggested disabling a reseller for 10 minutes and see if the CPU comes down. If it does then drill down the websites under that user. if that doesnt work try the mysql and if all else fails he will move the servers to rule that out also.

Is there a command to remove a domain from Plesk as I have tried removing a domain/subscription in Plesk and it will not remove it. Its a large sized website and it could be one of the reasons I think ?

Thanks again Martyn
 
Hi,

if you really have a large website and want to remove it as in delete it, it may take some time if it's really big.
Please note, that deleting a subscription from within Plesk actually deletes all files related to the subscription on the Server.

I would start with disabling it first.

Regards,
Kristian
 
Hi

I tried deleting it yesterday but its still there. Ive now disabled it. It seems to have deleted all the files, mail and databases but its still on Domains and subscription and saying 86GB (too big in my opinion and this may be down to it been migrated from CPanel). All sites on both servers were migrated from WHM/CPanel but as I said Server 1 is OK.

I have tried disabling the reseller accounts 1 by 1 for about 10 minutes and nothing changes on the load or the Wait IO on the CPU usage.

Looks like Im down to just switching nodes and hoping that fixes it.

Is there no way of checking per user what they are using.

Just thought I would attach my htop results and as you can see loads of httpd and its using the memory. Do you still think its the node ?

htop_serverb.png

Thanks again

Martyn
 
Hi,

just for the sake of it, could you please execute the following command on Server1 and 2 and paste both results?

# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync

This will write a 1GB File called "test". It should give you some output of how fast it was able to write that 1GB file.

dd is not intended for such tests. But it can help for investigation.

Thanks,
Kristian
 
Hi Kristian

I will do this later on today as I dont have access to the server at the moment.

What do you want me to post on here ? The htop after I run the command ?

Thanks

Martyn
 
Hi,

please post the output of the commands.
They might "hang" a while. But they should complete within 4 - 60 Seconds.

Regards,
Kristian
 
Hi Kristian.

These are the results from my 2 servers.

Server 1 is the good server but server 2 is slow

Server 1
[root@ServerA ~]# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB) copied, 39.2636 s, 27.3 MB/s


Server 2

[root@ServerB ~]# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB) copied, 56.8211 s, 18.9 MB/s

Thanks

Martyn
 
Last edited:
Hi,

did you remove the "#" infront of the command? :)

It should give you back something like this:
16384+0 Datensätze ein
16384+0 Datensätze aus
1073741824 Bytes (1,1 GB) kopiert, 10,1533 s, 106 MB/s
Click to expand...

Regards,
Kristian
 
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