Rescan SATA bus (aka hot-adding a SATA disk on a Linux guest in VMware without rebooting)

Mon, 24 Oct 2011 15:20:51 +0000

Linux supports hot-adding disks but whenever I add a new vdisk in VMware the new disk doesn’t show up unless I reboot, which defeats the purpose of hot-add. This command forces a rescan of the bus:

echo "- - -" > /sys/class/scsi_host/host0/scan

dmesg shows the new disk has been found:

Vendor: VMware Model: Virtual disk Rev: 1.0 
 Type: Direct-Access ANSI SCSI revision: 02
 target0:0:2: Beginning Domain Validation
 target0:0:2: Domain Validation skipping write tests
 target0:0:2: Ending Domain Validation
 target0:0:2: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127)
SCSI device sdd: 1048576000 512-byte hdwr sectors (536871 MB)
sdd: Write Protect is off
sdd: Mode Sense: 03 00 00 00
sdd: cache data unavailable
sdd: assuming drive cache: write through
SCSI device sdd: 1048576000 512-byte hdwr sectors (536871 MB)
sdd: Write Protect is off
sdd: Mode Sense: 03 00 00 00
sdd: cache data unavailable
sdd: assuming drive cache: write through
 sdd: unknown partition table
sd 0:0:2:0: Attached scsi disk sdd
sd 0:0:2:0: Attached scsi generic sg3 type 0

Now, why there’s no “rescan_sata” command is something I can’t fathom, but that’s Linux for you.

Hot-Plug on Evan Hoffman

Rescan SATA bus (aka hot-adding a SATA disk on a Linux guest in VMware without rebooting)