How to Mount, Copy Data, and Safely Eject Disks on a Production Server

Managing disks efficiently is a critical task for system administrators, especially in production environments. Mounting, copying data, and safely ejecting disks might seem routine, but on a production server, every step needs to be precise to avoid service interruptions or data loss. This guide will walk you through these steps, ensuring safety and reliability in your operations.

Why Is It Critical on a Production Server?

On a production server, improper handling of disks can lead to:

Data Loss: Unflushed writes or corrupted filesystems due to improper ejection.
Downtime: Mounting errors or unresponsive services if critical directories are mishandled.
Security Risks: Leaving unused disks mounted can expose sensitive data.

By following best practices, you ensure your production environment remains secure, stable, and efficient.

Step-by-Step Guide

1. Mounting a Disk

Identify the disk and its partitions using the lsblk command:

lsblk

In the example:

sdc 8:32 0 476.9G 0 disk

├─sdc1 8:33 0 476.9G 0 part

└─sdc2 8:34 0 32M 0 part

The sdc1 partition contains most of the data.

Create a mount point:

mkdir /mnt/sdc

Mount the partition:

mount /dev/sdc1 /mnt/sdc

Verify the mount:

ls /mnt/sdc

If the partition has a specific filesystem, use the -t option:

mount -t ext4 /dev/sdc1 /mnt/sdc

2. Copying Data

Once mounted, use cp or rsync to copy data:

Using cp:

cp -r /mnt/sdc/* /var/lib/vz/images/

Using rsync (recommended for large datasets):

rsync -av /mnt/sdc/ /var/lib/vz/images/

After copying, verify the data:

ls /var/lib/vz/images/

3. Safely Ejecting the Disk

Before removing the disk, unmount and power it off properly.

Unmount the Disk:

umount /mnt/sdc

If multiple partitions are mounted, unmount each one, e.g., umount /dev/sdc1.

Sync the Disk:

Flush pending writes to the disk:

sync

Power Off the Disk:

Use udisksctl (if available):

udisksctl power-off -b /dev/sdc

Alternatively, use eject:

eject /dev/sdc

If neither tool is available, manually remove the device from the kernel:

echo 1 > /sys/block/sdc/device/delete

Verify the disk is removed:

lsblk

Best Practices for Production Servers

Plan Ahead: Ensure the disk is not mounted on critical directories like /var or /etc during active use.
Use Backups: Always back up data before modifying disk configurations.
Automate with Scripts: Automate repetitive tasks using shell scripts to avoid human error.
Log Operations: Maintain logs of mounted disks and data transfers for auditing.

Conclusion

Handling disks on a production server requires meticulous attention to detail to prevent disruptions. By following this guide, you can mount, transfer data, and safely eject disks with confidence, ensuring your server's stability and security.