Contents
1. Disk Usage Check Script
1.1 Script Creation
| 
					 1 2  | 
						# cd /opt/script/ # vi disk_capacity_check.sh  | 
					
Contents of disk_capacity_check.sh
Configured to notify when disk usage exceeds 80%.
| 
					 1 2 3 4 5 6 7 8 9 10  | 
						#!/bin/bash #Designation of e-mail address to be notified MAIL="[your mailaddress]" DVAL=`/bin/df / | /usr/bin/tail -1 | /bin/sed 's/^.* \([0-9]*\)%.*$/\1/'` if [ $DVAL -gt 80 ]; then echo "Disk usage alert: $DVAL %" | mail -s "Disk Space Alert in `hostname`" $MAIL fi  | 
					
| 
					 1  | 
						# chmod 700 disk_capacity_check.sh  | 
					
1.2 Execution Confirmation
①Check current utilization
| 
					 1  | 
						# df -h  | 
					
It appears as follows
| 
					 1 2 3 4 5 6 7 8  | 
						Filesystem      Size  Used Avail Use% Mounted on udev            970M     0  970M   0% /dev tmpfs           197M   23M  175M  12% /run /dev/sda1        19G  3.8G   14G  22% / tmpfs           985M     0  985M   0% /dev/shm tmpfs           5.0M     0  5.0M   0% /run/lock tmpfs           985M     0  985M   0% /sys/fs/cgroup tmpfs           197M     0  197M   0% /run/user/1000  | 
					
②Create a dummy file to have at least 80% utilization (in the example, it is named "dummyfile" and is about 13G)
| 
					 1  | 
						# dd if=/dev/zero of=dummyfile bs=1M count=13000  | 
					
③confirmation
| 
					 1  | 
						# df -h  | 
					
Confirmation that it is 80% or higher
④Run disk space check script
| 
					 1  | 
						# /opt/script/disk_capacity_check.sh  | 
					
You will receive an e-mail to the e-mail address you have set up with the body of the message as "Disk usage alert : 94%".
⑤Delete the "dummyfile" you created.
| 
					 1  | 
						# rm dummyfile  | 
					
⑥Periodic Execution Setting
| 
					 1 2  | 
						# crontab -e 30 2 * * * /opt/script/disk_capacity_check.sh  | 
					
2. Log analysis tool logwatch installed
2.1 logwatch Install
| 
					 1  | 
						# apt -y install logwatch  | 
					
2.2 Edit logwatch configuration file
①Copy default configuration file
| 
					 1  | 
						# cp /usr/share/logwatch/default.conf/logwatch.conf /etc/logwatch/conf/  | 
					
②Change email address, etc.
| 
					 1 2 3 4 5 6  | 
						# vi /etc/logwatch/conf/logwatch.conf Line 54 : #MailTo = root   ← Comment out and add the following MailTo =[your mailaddress]  Line 87 : Detail = High  | 
					
2.3 Creating Directories
There is no directory used by the cache, so create one.
| 
					 1  | 
						# mkdir /var/cache/logwatch  | 
					
2.4 operation check
When logwatch is installed, cron is registered by default, so you will receive daily report emails.
If you want to check it immediately, do the following
| 
					 1  | 
						# /etc/cron.daily/00logwatch  | 
					
