How do I rescan drives I've expanded?

I frequently expand drives on my VMs. How can I rescan the drives without rebooting the server?

2 Answers

The easiest solution is to use scsitools script rescan-scsi-bus.

sudo apt-get install scsitools
sudo rescan-scsi-bus

To do it without installing a utility on 14.04:

echo '1' > /sys/class/scsi_disk/0\:0\:0\:0/device/rescan

IMPORTANT: Be sure to replace the 0:0:0:0 with the appropriate disk for your purposes.

Example for system disk without reboot:

• Rescan the bus for the new size:

  # echo 1 > /sys/block/sda/device/rescan

• Expand your partition (works with ansible):

  # parted ---pretend-input-tty /dev/sda resizepart F 2 Yes 100%
  - F for Fix
  - 2 for partition
  - Yes to confirm
  - 100% for whole partition

• Resize it:

  # resize2fs /dev/sda2