LINUX AND VMWARE STUFF

This Blog is to share our knowledge and expertise on Linux System Administration and VMware Administration

Wednesday, April 25, 2018

How to free the disk space from deleted files in which PIDs are still running?

Wednesday, April 25, 2018 0
Sometimes we have removed large size of logfiles or files from linux server as part of housekeeping. But it will not release the disk space while running lsof command

[root@testserver ~]# lsof / | grep -i deleted
sh          3716       root    4w   REG  249,0  2269000 3342481 /var/log/cellos/mcelogd-mon.log (deleted)
sh          3716       root    5w   REG  249,0  2333681 3342525 /var/log/cellos/mcelogd-mon.trc (deleted)
tgtd        4144       root    4w   REG  249,0 26684869 3342480 /var/log/cellos/qd.log (deleted)
tgtd        4144       root    5w   REG  249,0 27453138 3342483 /var/log/cellos/qd.trc (deleted)
tgtd        4145       root    4w   REG  249,0 26684869 3342480 /var/log/cellos/qd.log (deleted)
tgtd        4145       root    5w   REG  249,0 27453138 3342483 /var/log/cellos/qd.trc (deleted)
iscsiuio    4592       root    4w   REG  249,0 26684869 3342480 /var/log/cellos/qd.log (deleted)
iscsiuio    4592       root    5w   REG  249,0 27453138 3342483 /var/log/cellos/qd.trc (deleted)

Normally we need to stop the logging service (syslog) before deleting the log files or stop the service which is related to the files.
Stopping  log collection on running server is not good practice.

Then how to solve the issue?

Free the Disk Space

Find the PID of deleted process, go to /proc then nullify it.

[root@testserver ~]# cd /proc/3716/fd
[root@testserver fd]# ls -al
total 0
dr-x------ 2 root root  0 Apr  9 17:08 .
dr-xr-xr-x 9 root root  0 Apr  9 17:08 ..
lrwx------ 1 root root 64 Apr  9 17:08 0 -> /dev/null
l-wx------ 1 root root 64 Apr  9 17:08 1 -> /var/log/exadatatmp/__imglog_stdout__.tFvWrjjEZTPOJWm3racIEPF5W9YQqMI3
lrwx------ 1 root root 64 Apr  9 17:08 10 -> /dev/null
lrwx------ 1 root root 64 Apr  9 17:08 11 -> /dev/null
l-wx------ 1 root root 64 Apr  9 17:08 2 -> /var/log/exadatatmp/__imglog_stderr__.tFvWrjjEZTPOJWm3racIEPF5W9YQqMI3
lr-x------ 1 root root 64 Apr  9 17:08 255 -> pipe:[21686]
l-wx------ 1 root root 64 Apr  9 17:08 4 -> /var/log/cellos/mcelogd-mon.log (deleted)
l-wx------ 1 root root 64 Apr  9 17:08 5 -> /var/log/cellos/mcelogd-mon.trc (deleted)

The process ID 3716 running on 4w (write mode).

[root@testserver fd]# ls -al 4
l-wx------ 1 root root 64 Apr  9 17:08 4 -> /var/log/cellos/mcelogd-mon.log (deleted)

We can release the space by nullify this file.

[root@testserver ~]# >/proc/3716/fd/4
[root@testserver ~]# lsof / | grep -i deleted | grep -i 3716
sh          3716       root    5w   REG  249,0        0 3342525 /var/log/cellos/mcelogd-mon.trc (deleted)

Alternate way, we can compress the file or we can kill the PID if not needed.
Tags # Linux General Continue Reading
By v�o l�c No comments:
Labels:

Thursday, April 19, 2018

Facter command in Linux

Thursday, April 19, 2018 0
Facter command is used to Collect and display facts about the current server. The library behind Facter is easy to expand, making Facter an easy way to collect information about a system information such as hardware details, network settings, virtualization type and kernel/OS information from within the shell or within Ruby. If no facts are specifically asked for, then all facts will be displayed.

If we want to use facter command, we need to install facter rpm.

Display all facts

[root@testserver manifests]# facter
architecture => x86_64
augeasversion => 1.1.0
bios_release_date => 01/06/2018
bios_vendor => Xen
bios_version => 4.4.4OVM
blockdevice_xvda_size => 53687091200
blockdevices => xvda
domain => puppet.test.com
facterversion => 2.4.4
filesystems => ext4,iso9660
fqdn => testserver.puppet.test.com
gid => root
hardwareisa => x86_64
....
....
uptime_days => 62
uptime_hours => 1491
uptime_seconds => 5368909
uuid => 0004FB00-0006-0000-7071-48CB71E70F8A
virtual => xenhvm

Display a single fact

[root@testserver ~]#  facter interfaces
eth0,eth1,eth2,lo

Facts format as JSON

[root@testserver ~]# facter --json architecture kernel  uptime timezone puppetversion bios_vendor
{
  "timezone": "CAT",
  "uptime": "62 days",
  "architecture": "x86_64",
  "kernel": "Linux",
  "bios_vendor": "Xen",
  "puppetversion": "3.8.1"

Facts format as YAML

[root@testserver  ~]# facter --yaml architecture kernel  uptime timezone puppetversion bios_vendor
---
bios_vendor: Xen
kernel: Linux
uptime: 62 days
timezone: CAT
architecture: x86_64
puppetversion: 3.8.1

Facter will produce output by below format.
a. JSON
b. YAML
c. Plaintext
Tags # Linux General Continue Reading
By v�o l�c No comments:
Labels:

Thursday, April 12, 2018

How to change the default login shell by command line in linux server?

Thursday, April 12, 2018 0
By using chsh command we can change the default login shell to other shell.

 By using -l option we can list the available login shell on linux server.

 [root@testserver ~]# chsh -l
/bin/sh
/bin/bash
/sbin/nologin
/bin/dash
/bin/tcsh
/bin/csh
/bin/ksh

 Then which user login shell need to change, we can change by below command. (If a shell is not given on the command line, chsh prompts for one)

 [root@testserver ~]# chsh hygmtng7
Changing shell for hygmtng7.
New shell [/bin/ksh]: /bin/bash
Shell changed.

 Before
[root@testserver ~]# cat /etc/passwd | grep -i hygmtng7
hygmtng7:x:20009:20009::/gmtng7/hyperion:/bin/ksh

 After
[root@testserver ~]# cat /etc/passwd | grep -i hygmtng7
hygmtng7:x:20009:20009::/gmtng7/hyperion:/bin/bash
Tags # Linux General Continue Reading
By v�o l�c No comments:
Labels:

Thursday, April 5, 2018

How to use --exclude option in du command

Thursday, April 05, 2018 0
du command is used to estimate file space usage.

 Sometime we need to exclude some folder or files while running du command.
For that we can use below option to achieve that.

 [root@testserver /]# du -sh * --exclude=repository --exclude=oem1

 The above command will exclude the repository & oem folder  under / path.

 Hope it helps.
Tags # Linux General Continue Reading
By v�o l�c No comments:
Labels: