The Fat Bloke Sings: Thoughts from a Fat Bloke

In the spirit of, "Hey we fixed a bunch of bugs, why hold on to them?" VirtualBox 3.0.12 was released today.

You could read about the fixes or just go get the new version. 

-FB 

The hard-drive(s) of your virtual machines are simply files which are stored typically on the host's filesystem. On my Mac they're in 

~/Library/VirtualBox/HardDisks/

VirtualBox understands several disk formats including:

• .vdi or "Virtual Disk Image", the native format for VirtualBox
• .vmdk - VMware's format
• .vhd - Microsoft's format

This means that if you have an existing hard drive from another virtualization platform, you can plug it into a VirtualBox vm by telling the system about it using the Virtual Media Manager...

 And then configuring it in the vm's Storage configuration dialog (or via the command line):

Given that VirtualBox not only understands, but can also create, these different formats, one obvious question is "what is the difference?" or "which one is best?" 

One of the VirtualBox team (thanks Klaus) explained:

"The major difference is that VDI uses relatively large blocks (1MB) when growing an image, and thus has less overhead for block pointers etc. but isn't ultimately space efficient in the sense that if a single byte is non-zero in such a 1MB block the entire space is used.
VMDK in contrast uses 64K blocks, and thus has more management overhead and generally a bit less disk space consumption
What offsets this is that VDI is more efficient when it comes to snapshots."

So now you know!

- FB 

VirtualBox marches on with the new version 3.0.6 maintenance release focused on performance and stability. If you use AMD, then this is Christmas morning And a few Snow Leopard wrinkles were ironed out too. 

Version 3.0.6 also has a few changes in support of the embryonic VirtualBox Web Console project. 

The 3.0.6 maintenance release was made available to download from the Usual Places earlier today.

For a fuller list of fixes check out the ChangeLog. 

-FB 

When I create new Virtual Machines, or guests, in VirtualBox I tend to skimp a little on the size of the virtual hard disk I create because I'm trying to save on host disk space. And this tends to come back and bite me when the guest quickly fills the disk and I run out of disk space in the guest. So you think, "wait a minute, this hard disk is just a file, so why can't I make the file bigger?".

The problem here is that, yes, to the host system it is just a file, but to the guest it is a hard disk and they're not expected to suddenly grow. So if or when they do, you need to tell the guest OS about this, by modifying the partition table too.

So here are a few options that you can use to deal with lack of disk space in the guest:

1. Compact the disk

One option is to not grow the disk at all but reorganize the data on it. Achim told us "How to Compact your Virtual Disks" last month. Note that you don't need to mess around with disk partitions with this option. 

2. Create a new bigger disk 

You could simply create a new bigger disk and copy over the old data  but you still need to tell the guest that the new hard disk has bigger partitions. Here's a step by step guide to doing this.

3. Create a bigger disk to start with but with a smaller root partition

One of the VirtualBox team (thanks Frank!) gave me this tip to creating large virtual disks while controlling host disk space at the same time.

"Instead of creating a dynamically growing disk image with, for instance 20GB, the user should create a large disk image, say, 100GB, but he should only partition the first 20GB by the guest. (ed - you typically get the chance to do this during OS install). Doing so, the disk image will never occupy more than 20GB (plus some maintenance information) as long as the guest doesn't need more. Once the guest is short in disk space, simply increase the guest partition using some common tool, for instance boot the guest with a Ubuntu Jaunty LiveCD and use the Partition Manager to increase the guest partition to your needs (that application can handle NTFS partitions as well). "

4. Using a networked storage server.

If you are using VirtualBox's built-in iSCSI support to a networked storage server such as Sun's Storage 7000 systems, or maybe simply a Solaris server running as an iSCSI target with ZFS, then you can resize the disk easily using:

# zfs set volsize=10G poolname/volname

But you still need to repartition this disk, as you need to do in 2 and 3 above too.

Hope one of these works for you.

- FB 

Good news! VirtualBox 3.0 is released. This is the  release where guests went SMP (multiple vCPUs).  And to show what that means here's a screenshot of a MacBook Pro (Intel Core 2 Duo) running:

• Windows Server 2008 with 4 vCPUs (left hand side);
• Ubuntu Server with 2 vCPUs (right hand side);

If you know what you are doing and you like to live dangerously, you might want to read about the VirtualBox 3.0 Beta which was made available this week.

-FB 

Even though you may be away from the office attending a conference, the rest of the world moves on and you quite often need to keep up with your day job. At JavaOne this year, Sun provisioned 21,000 Virtual Desktops for the attendees to use to stay on top of things. This blog entry describes briefly how this was done using VirtualBox and Sun VDI...

User's experience

Dotted around the Moscone Center were hundreds of Sun Rays. These were in the Lobby Areas,

Underpass between North and South Halls, 

and Cyber Lounge areas in the Pavilion.

Every JavaOne attendee was given a smartcard as part of their Welcome Kit on registration. And all you needed to do to get your Virtual Desktop was insert this into the nearest free Sun Ray.

The user can then choose which type of Virtual Desktop they want from:

• Windows 7 
• Ubuntu 8.10
• OpenSolaris 2009.06 

Under the hood:

The first time you make this choice your Virtual Desktop virtual machine (vm) is created based on a template in Sun VDI. The virtual machine configuration is held in a MySQL database and the virtual disk image is quickly cloned from the template using a feature of ZFS which underpins the Sun Storage 7000 servers that were in use. Then Sun VDI chooses a VirtualBox server (based on load) and launches the new vm on that server, with the configuration and iSCSI target id that uniquely identifies the new virtual disk.

When you pull your card out the vm suspends after a short period which means resources can be freed up for other users.

When you re-insert your card and launch a previously created Virtual Desktop, the vm is restored from disk (note that this can be to a different VirtualBox server than the original session ) and you are good to go.

Here is my Windows 7 Virtual Desktop.

Administrator Experience 

To manage the 21,000 virtual desktops we had 2 guys (admittedly smart guys).

And the whole thing was powered by a single rack:

The rack consisted of:

• 4 VDI servers - 4 Sun Fire X4450, each with 4 CPUs and 64 GB memory.
• 5 VirtualBox servers - 5 Sun Fire X4450 servers, each 4 CPUs, 6 cores per CPU and 64 GB of memory.
• 3 Storage servers - 3 * 7210 Unified Storage servers.

This was vastly over-spec'ed as we could see using the Analytics of the storage servers:

Thanks to Christian and Thomas (our architects and admins for the week) and kudos to Dirk's and Achim's teams.

- FB 

Quick one: Version 2.2.4 was made available for download last night from the Usual Places.

What got fixed is listed here.

- FB 

One of the really cool and really powerful features introduced in version 2.2 is the ability to export and import virtual appliances. A Virtual Appliance consists of:

• description of one of more virtual machines in an OVF file;
• a set of one or more virtual disk images.

 With VirtualBox you can now easily create virtual appliances by simply exporting your vm's directly from the VirtualBox GUI or on the command line. 

And of course you can import just as easily as you would expect.

For details of how it works and why you might want to do this here's a 9 minute movie. There are chapter markers for Import and Export sections if you want to skip thru it.

-FB

VirtualBox 2.1 introduced 3D acceleration in Windows guests and 2.2 introduced support for Linux and OpenSolaris guests. Here's a short video about how this feature can deliver the Compiz effects in a Linux guest.

Fat Bloke had a little time off lately after the excitement of releasing 2.2. But the Buzz around VirtualBox didn't let up and was fueled even more by events such as the launch new versions of Ubuntu and Mandriva, Microsoft's XP-mode with Windows 7 and, of course, Oracle's move for Sun.

So FB has been working hard to catch up and sift thru all the great stuff that has been published in the last couple of weeks. If you want to keep up with the VirtualBox zeitgeist you might want to follow the VirtualBox Buzz blog.

-FB