Here’s another great article from TechHead guest contributor, James Pearce.   James is a Kent based qualified accountant, currently working in information security and technical architecture with  most of his  time “being spent on virtualisation and business continuity at the moment”.

James’ previous article on his experiences installing and running a Dell PERC 5i controller inside his HP Proliant ML115 G5 VMware ESXi home lab server was really well received and I’m sure you’ll find this one just as interesting.

Why WHS?

If you have a TechNet Plus subscription you have access to Windows Home Server (WHS), and if not the OEM version is about £80.

I’ve been using it to provide scheduled disk based backups of both my VMs (all running on vSphere ESXi) as well as my physical machines. This makes restoring complete machines at any point-in-time, or files from them, a snap and of course protects against a disk failure.

WHS has some other nice features – its SSL web site provides RDP Proxy, allowing console access to VMs and the VI Client from anywhere, share access, and comes with a free GoDaddy certificate and homeserver.com domain name.

WHS Backups

The computer backup functionality in WHS is excellent. Despite having practically no configuration, it’s highly efficient on disk space, simple to use to restore individual files or indeed an entire computer, and can cope with all Microsoft OS’s including Windows 7 & Server 2008, even with BitLocker and EFS volumes. Microsoft include a bootable recovery CD, which makes tiresome jobs like laptop hard disk upgrades a doddle, and can be used within ESXi VMs too.

The system is based around a snapshot taken with the volume shadow service (VSS) with compression and de-duplication – any disk block that appears on multiple backups is only stored once. Being VSS based, the backups should be reliable and the actual storage needed to backup multiple machines, because of the de-duplication, is relatively small. Enterprise backup solutions are also in on this act, with disk-based systems like ExaGrid 2TB solution coming in at an eye-watering £14,000 and boasting 50:1 compression – similar to WHS!

Limitations

For £80 there are some limitations. WHS can handle only 10 machines (by an enforced license restriction), and this includes machines that are permanently off-line. It also can’t join a domain and doesn’t like to co-exist with SBS.

On the plus side, two WHS instances can co-exist, doubling the machine count to 20, and WHS specific antivirus products (like Avast) include licenses for all ten clients.

Installing WHS on ESXi

Minimum machine spec for WHS is 512MB RAM and 80GB HDD (via the LSI controller) and its just 32-bit Windows Server 2003 as far as ESXi is concerned.

If the server doesn’t have RAID, failure of any of the other disks in the ESXi server can be protected against with minimal outlay by using a dedicated disk for the WHS VM.

The WHS installer seems to be based on Windows XP, so it doesn’t support either the BusLogic or the LSI SCSI controllers, displaying the message “Hard drive capable of hosting Windows Home Server was not found” during installation. Fortunately all the drivers needed fit on a floppy image, which can be downloaded here.

Attach the VLP and click “Yes” at the prompt, and navigate to a:\scsi\symmpi. The setup utility then formats the volume and installs the software – the whole process takes about an hour.

Once it’s running, install the VI Tools as usual and, if you want to use the remote access capabilities, forward ports 443 and 4125 to the new WHS (and 80 to avoid typing https:// to access it). A static IP isn’t needed as the WHS periodically registers the IP address in use.

Managing WHS

Everything in WHS is managed through the WHS console (an RDP shared app) which is simple to use and highly intuitive. Once the ‘connector’ is installed on a client, the WHS console is accessed by right-clicking on the WHS icon in the system tray (and is also available remotely through the web interface).

Configuring the Clients

The WHS connector component needs to be installed on each client and is found at http://[whs]:55000/. I’ve successfully tested Windows 2000, XP, 2003, Vista, 7 and 2008 in both 32- and 64-bit flavours.

Configuring the Backups

There’s nothing to it – check you’re happy with the backup window and the retention periods preset through the WHS console Settings section. Long retention periods don’t necessarily require much more disk space because of the de-duplication technology, as only changes between each backup add to the storage required.

The backup component provides a summary of each machine backed up, a simple double-click providing a full backup history for that machine and individual file restore functionality.

The default backup window is fairly long, but this can be customised if required.

File Based Restores

The WHS backups can be used for (virtual) bare-metal restores, but can also mount the volumes in each backup as a drive on any PC with the WHS connector installed via the WHS console.

Once the required backup has been located, simply click on ‘Open’. WHS connector then installs a device driver on the PC being used to access the backup, mounting the volume as local drive Z after a bit of a delay while the server reconstructs the backup. Files can be opened or copied, but not edited.

Restoring a Complete (Virtual) Machine

WHS includes a bootable restore CD, which seems to be Vista based. When using through a vm, set the VM type to Vista 32-bit and no additional drivers are required. It will also work configured as an XP VM, but network and storage drivers are needed (from here).

The restore process is wizard driven and so fairly self explanatory. After finding the server (which must be on the same subnet as it’s located through broadcast), a list of machines is presented followed by a list of available backups.

One needless step is that the unformatted disk presented to the guest (no different to a new hard disk obviously) needs to be manually formatted with Disk Manager. The wizard at least points this out and provides the tool, so it only adds a few clicks. Be sure to select quick format, especially on larger volumes, and note the extra partition in Windows 7 installs needs to be manually created as well.

Once the restore is complete, turn off the and reset the VM properties to match whatever the ‘hardware’ and OS configuration should be. The SCSI controller and disk options in particular will stop the VM booting if different from when the backup was taken.

Restore Throughput

The process doesn’t seem to put too much strain on my lab box:

• ~25% CPU on both WHS and the VM running the restore (both 1 vCPU)
• ~13MB/s disk IO and Network usage on the WHS VM
• 30MB/s+ on the restoring VM (~100GB/hr).

Potential Problems

I found that if changing the volume size significantly, the restore would sometimes fail, and if running the restore through an ‘XP-Pro’ VM, the BusLogic SCSI controller couldn’t be used; it would fail part way through every time.

In Summary

WHS provides space-efficient backup for Windows based computers, both physical and virtual.  It has reasonably light system resource requirements and the restore process works fine through a VM.  The added extras of remote access to any powered on machine through RDP proxy, web file share interface, and free domain name and SSL certificate are handy to have – and it’s reliable too.

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