What this how-to will provide is a script that runs hourly via systemd timers, checking to see if your ZFS ZPool is in any status other than online and then emailing you via Gmail if it is. These specific instructions are written for Arch Linux but can likely be adapted to other distributions easily.
Installation
ZFS Mail Script
sudo vim /root/zfsmail.sh
#!/bin/bash
ZPOOLSTATUS=$(zpool status | grep 'state:' | cut -c 9-)
if [ "$ZPOOLSTATUS" != ONLINE ];
then
TO="[email protected]"
SUBJECT="ALERT: ZPool $ZPOOLSTATUS"
BODY="Your precious ZPool is $ZPOOLSTATUS. Get in there and fix it!"
echo "$BODY" | /usr/bin/mail -s "$SUBJECT" "$TO"
else
exit 0
fi
Install MSMTP
Rather than set up a full-blown MTA, we'll use MSMTP (Mini SMTP) to simply forward email to Gmail's SMTP servers for sending. I use and recommend Pacaur for an AUR helper, and it also can install non-AUR packages.
pacaur -S msmtp msmtp-mta
Configure MSMTP
Edit the from, user, and password fields.
sudo vim /root/.msmtprc
# Accounts will inherit settings from this section
defaults
auth on
tls on
tls_trust_file /usr/share/ca-certificates/mozilla/Thawte_Premium_Server_CA.crt
# Gmail address
account gmail
host smtp.gmail.com
port 587
from [email protected]
user [email protected]
password enterpassword
tls_trust_file /etc/ssl/certs/ca-certificates.crt
#Default account
account default : gmail
Hourly Timer
This will create a systemd timer that runs every hour. Output will be logged to the journal and, since Arch already uses systemd, no installation of cron is required.
sudo vim /etc/systemd/system/timer-hourly.timer
[Unit]
Description=Hourly Timer
[Timer]
OnBootSec=5min
OnCalendar=hourly
Unit=timer-hourly.target
[Install]
WantedBy=basic.target
Hourly Timer Target
sudo vim /etc/systemd/system/timer-hourly.target
[Unit]
Description=Hourly Timer Target
StopWhenUnneeded=yes
Hourly Timer Directory
Service files placed in this directory will be run automatically every hour.
sudo mkdir /etc/systemd/system/timer-hourly.target.wants
ZFS Mail Service
This is the actual systemd service that will execute the bash script.
sudo vim /etc/systemd/system/timer-hourly.target.wants/zfsmail.service
[Unit]
Description=ZFS Mail
[Service]
Type=forking
ExecStart=/root/zfsmail.sh
Enable Hourly Timer
Finally, enable the hourly timer.
sudo systemctl enable timer-hourly.timer
Verification
The very last step is to verify that it is working, which we can do by checking the journal.
Viewing Status
sudo journalctl _PID=1 -n
Successful Run
May 23 17:00:04 austin-nas systemd[1]: Starting ZFS Mail...
May 23 17:00:04 austin-nas systemd[1]: Started ZFS Mail.
May 23 17:00:04 austin-nas systemd[1]: Starting Hourly Timer Target.
May 23 17:00:04 austin-nas systemd[1]: Reached target Hourly Timer Target.
May 23 17:00:04 austin-nas systemd[1]: Service timer-hourly.target is not needed anymore. Stopping.
May 23 17:00:04 austin-nas systemd[1]: Stopping Hourly Timer Target.
May 23 17:00:04 austin-nas systemd[1]: Stopped target Hourly Timer Target.
Conclusion
That's it! I'm sure there are a million way to do the same thing, but if there's something clearly better please comment and let me know!