jeredding/systemd-ephemeral-drives

systemd-ephemeral-drives

Systemd thinks it knows best, and getting ephemeral data partitions correctly configured isn't a single command.

This is based off of some work from bhuisgen put together with a much more focused purpose. Scripts have been refactored and any unnecessary cruft for the use case has been eliminated. The instructions are basically the same to get started.

Dependencies

# apt install make parted lvm2

If you have multiple ephemeral disks, you can use software RAID to increase IO performance:

# apt install mdadm

## ephemeral-disk

This script prepares the ephemeral disks of an EC2 instance at each system boot by creating a swap partition (if enabled in configuration) and a data partition wich will be mounted in the directory /mnt/data. If the partitions are already created, nothing is done except mounting them. After mounting, the service starts by dependency all required services.

LVM is used like this:

• a LVM volume group ephemeral of all disks
• a LVM logical volume swap for the swap partition
• a LVM logical volume data for the data partition

The LVM volume group will have sufficient free space to allow snapshot creation and backup with the script ephemeral-backup.

Installation

# cd ephemeral-disk/

# cp ephemeral-disk.dist ephemeral-disk
# vim ephemeral-disk

# cp ephemeral-units.service.dist ephemeral-units.service
# vim ephemeral-units.service

# make install

### Usage

Start the ephemeral disk services:

# make enable
# make start
# lvs
# cd /mnt/data

To be sure verify your bootorder after a system restart:

# systemd-analyze plot > bootorder.svg

The unit ephemeral-units.service must be started before all units using the ephemeral storage.