eSATA Hot Plug/Unplug

Install scsitools and hdparm

Hot Plug

If your eSATA drive is not detected when you plug it in, there are some options to solve the issue without reboot with the eSATA plugged in.

Option 1a

# echo 0 0 0 | tee /sys/class/scsi_host/host*/scan
[Detect new eSATA drives - ArchWiki].

    Or

Option 1b

# rescan-scsi-bus

2. Mount disk

Safely Unplug

1. Unmount disk(s)

2. Force drive to enter the standby mode

# hdparm -y /dev/sdb

3a. Power drive off, or

3b. If you want to spin drive up again

# sg_sat_set_features -f 7 /dev/sdb

Power-up HDD in standby - Arch Linux Forums
HDD Power-Up in Standby - Super User