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

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.

Advertisements

Displaying currently-playing iTunes track in the Mac menu bar

In an attempt to teach myself Objective C, and because I couldn’t find anything that did what I wanted, I wrote a little utility to display the currently-playing iTunes track in the Mac taskbar. Originally I had it display the full track name right in the taskbar but it was too much text for such a small space (especially on a 1440×900 screen), so now you click a little musical note and it shows you the info in a menu.

Here’s a screenshot:

The code is all in github. If you’re looking for a similar utility, and are brave enough to try my first-ever Obj-C app, you can download it here. But the freshest version will probably be in the github project.

As an aside, I was surprised at how easy it was to cobble this together having never written ObjC before. I found some good examples that I mostly ripped off, but it was still remarkably easy to have the app listen to iTunes for track changes, etc.