Thursday, July 25, 2019

How to change timezone from CEST to UTC on SUSE Linux Enterprise Server

Some time Linux admin need to configure timezone for Linux host,reason may requirement from application or database team or sometime wrong timezone configuration by Linux admin.

So, Lets see how to configure timezone from CEST to UTC.


Step 1: Before changing timezone please note previous timezone details by using following command.

root@linuxhost:/root : date
Thu Jul 18 16:30:38 CEST 2019

root@linuxhost:/root : cd /etc
root@sedcacoi0060:/etc : ls -lrt /etc/localtime
lrwxrwxrwx 1 root root        33 Jul  3 08:57 localtime -> /usr/share/zoneinfo/Europe/Berlin

Step2 :

Now here we need to change time zone to UTC. Before changing this setting first note previous setting in notepad file.

Step 3:

Excute following command to change timezone to UTC.

#rm /etc/localtime
#ln -sf /usr/share/zoneinfo/UTC /etc/localtime

Step 4:

Confirm change is done or not by using following command.
#ls -lrt /etc/localtime
lrwxrwxrwx 1 root root 23 May  6 12:05 /etc/localtime -> /usr/share/zoneinfo/UTC

Also using date command admin can confirm that timezone changed from CEST to UTC.


Thu Jul 18 02:40:24 UTC 2019

Thanks !!!

Tuesday, July 23, 2019

auto mount issue on AIX hacmp cluster

Hello everyone ,

Today i am discussing on issue which i faced while umounting nfs mount on AIX hacmp node .on aix hacmp node netapp filer was mounted and we received request to umount that nfs mount permanently.

We executed "#umount"  command to perform this ticket and updated to responsible team, but after some time found that mount point auto mounting. we thought that somebody has mounted and did umount again, but that mount point mounting again.

so we decided to check configuration file /etc/ on AIX cluster node and found that there is entry for that mount point.

/etc/ entry:

/share/data -bg,intr,soft,rw  nfsServername:/vol/xxxxx_cifs_nfs_vol017/share_data

After comment

#/share/data -bg,intr,soft,rw  nfsServername:/vol/xxxxx_cifs_nfs_vol017/share_data

To sort out auto mount issue we commented nfs mount entry in /etc/ and then umounted /share/data.

***always take backup of configuration file before editing.

Thanks !!!!!!!!!!!

umount AIX nfs mount point by removing entry in /etc/filesystems

Sometime while umounting nfs mount point, AIX admin also need to remove entry in /etc/filesystems. Let see how we can do this using 2 different method.

1. Using rmnfsmnt command.
2. Using umount command and then remove entry manually from /etc/filesystems.

In first method we need to execute following command

Lets assume that nfs mount point name is "/nfs_aix", so command is like

#rmnfsmnt -f /nfs_aix -B

-f  specify mount point name
-B Remove /etc/filesystems entry for mentioned mount point.

Second method is like below

1. umount /nfs_aix
2. Take backup of /etc/filesystems
3. find nfs mount point entry /nfs_aix  in /etc/filesystems and remove that entry.
4.confirm whether entry removed from configuration file .

Thanks !!!