• How to create systemd service unit in Linux
• Set systemd service to execute after fstab mount
• DigitalOcean Tutorials systemd:
  • How To Use Systemctl to Manage Systemd Services and Units
  • Understanding Systemd Units and Unit Files
  • How To Use Journalctl to View and Manipulate Systemd Logs
  • Systemd Essentials: Working with Services, Units, and the Journal
• NFS mount via systemd
• How to start systemd service after NFS mount in Linux

systemd-analyze – Find System Boot-up Performance Statistics in Linux

man journald.conf manual page for journald.conf
man journalctl manual page for journalctl

Edit sudo vim /etc/systemd/journald.conf make variable Storage=persistent to make journald store the journal files in /var/log/journal, this will create directory if necessary. This also ensure log files are available from previous boots.
sudo systemctl force-reload systemd-journald to reload journald or restart instead sudo journalctl -u systemd-journald to check status of journal

some links:
Use journalctl to View Your System's Logs

timedatectl to print current time date on cli
Date to print basic time date only on cli
timedatectl list-timezones to set available time zones
sudo timedatectl set-timezone australia/perth to set timezone

Some links:

• Arch Linux systemd/Timers
• Putorius Using systemd Timer Units to Schedule Jobs
• Linux.com Systemd Timers: Three Use Cases

• Freedesktop.org systemd.time — Time and date specifications and systemd.timer — Timer unit configuration