Dec 202011
 

As of WHM 11.30, the nameservers’ IP assignments are now read from the Zonefiles and actual DNS queries after recent updates. If you are not seeing the needed IPs in /etc/nameserverips please do not attempt to edit that file, as it is now overwritten by cPanel.

Check under WHM: Main >> DNS Functions >> Nameserver IPs for current nameserverips

(Solutions may depend on the cPanel version)

Problem
The updated A entries and/or NS entries are not retained:
Solution(s)
Add the needed nameservers to the /etc/hosts file

vim /etc/hosts

Add (append) a new line, one per IP, onto the existing hosts file such as:

123.456.789.012     ns1.domain.com

OR

123.456.789.012     ns1.domain.com ns2.domain.com

Then run the updatenameserverips script:

/scripts/updatenameserverips

Check under WHM: Main >> DNS Functions >> Nameserver IPs again to see if it worked, if not continue

Delete the nameserverips.cache file

rm  /var/cpanel/nameserverips.cache

Then modify /var/cpanel/nameserverips.yaml to suite

vim /var/cpanel/nameserverips.yaml

Then run the updatenameserverips script again

 Posted by at 3:21 pm
Dec 042011
 

From http://balajitheone.blogspot.com

IO wait load tracking to a process.

How to identify what processes are generating IO wait load.
————————————————————-

An easy way to identify what process is generating your IO Wait load is to enable block I/O debugging. This is done by setting /proc/sys/vm/block_dump to a non zero value like:

echo 1 > /proc/sys/vm/block_dump

This will cause messages like the following to start appearing in dmesg:

bash(6856): dirtied inode 19446664 (ld-2.5.so) on md1

Using the following one-liner will produce a summary output of the dmesg entries:

dmesg | egrep "READ|WRITE|dirtied" | egrep -o '([a-zA-Z]*)' | sort | uniq -c | sort -rn | head
    354 md
    324 export
    288 kjournald
     53 irqbalance
     45 pdflush
     14 portmap
     14 bash
     10 egrep
     10 crond
      8 ncftpput

Once you are finished you should disable block I/O debugging by setting /proc/sys/vm/block_dump to a zero value like:

echo 0 > /proc/sys/vm/block_dump

Nice…

From http://balajitheone.blogspot.com

 Posted by at 9:14 am