Category Archives: DICE

My Favourite VirtualBox Settings (as of 2.2.2)

VirtualBox improves with every release, and is now seems to be at a stage where it can be more than a mere curiosity for DICE users, as proven by our LCFG release test VMs, the ongoing Desktop Virtualisation project and my use of a VM as an emergency standin for failed server hardware.

Configuring the virtual machines is a process of trial-and-error, and not all settings suit all guests.  However as of version 2.2.2, this is my annotated list of my current ‘best’ DICE-on-DICE configuration:

Basic Settings:

OS Type: Linux -> Red Hat (32/64-bit)
Base Memory: (>= 384Mb ample for low-load commodity servers, but >= 1Gb apparently required for 64-bit guests)
Video Memory: >= 8Mb (for full-screen X on a DICE Host)
Boot Order: Hard Disk (with PXE on-demand only)
ACPI: Enabled (allows safe unattended shutdown, if nothing else!)
IO APIC: Disabled (causes massive clock skew if enabled)
VT-x/AMD-V: Enabled (provides some performance improvement, if mainly to host)
Nested Paging: Disabled (not yet supported on our hardware, but no harm in enabling)
PAE/NX: Enabled (of course PAE is not applicable on 64-bit, but there’s no reason to disable it on either arch)
3D Acceleration: Disabled (but worth enabling if you are using the Guest as a desktop, with Guest Additions)

Sound:

The SoundBlaster 16 device is detected, and can be used, by a DICE guest.

Note that any sound device will cause problems if you plan on running your guest ‘headless’.

Network:

Both Intel Pro (Desktop) and PCNet-Fast III devices work, providing 1Gbit and 100MBit network connections, respectively.

I’ve noticed that on Optiplex 755 hardware (on either virtual device), for each PXE boot request made by a guest, two requests are sent by the host: the first with the hosts’s MAC, and the second with the guest’s.  Clearly not ideal but I’ve not made any more detailed investigation into this: my DICE-install PXE boots are necessarily attended, and therefore easily restarted on failure.

Details on the specifics of bridged-mode network configuration can be found on the official DICE VirtualBox wiki page.

Hard Disk:

The standard ATA controller works very well. DICE + SATA will be tested soon.

Expect me to change my mind over time, not least because I note that 2.2.4 is already available…

LCFG repository access on a Mac

Mac OS X Leopard’s subversion client (as of 10.5.6), or more accurately its subversion client’s dependency library libneon, appears to be slightly broken when used with Kerberised WebDAV.

As you’d expect, subversion 1.6 as provided by MacPorts does not have this flaw.

This blog entry (LI Tech Blog » Patching neon on OS X 10.5 for GSSAPI authenticated SubVersion) provides a solution to the problem.  In summary: patch or replace libneon.

An interesting point is that the Mac build of the ‘pysvn’ subversion libraries does not appear to have been affected by this bug.

Passive Monitoring

Familiar?

Profile Translation WARNING 1/4 WARNING: Service checked passively

If you’re getting this warning for a service which is checked passively by default, the solution is simple: just disable active checking!

It seems as if a more appropriate message would be something along the lines of “WARNING: cannot perform active checking” or similar. Still, now I know, if it saves someone else attempting to re-enable every option three times over… or reading documentation…