Windows Home Server is the only consumer level operating system to offer a software implementation of RAID 5. Is it really worth considering as an option though?
Ease of use
RAID 5 Setup in Computer Management
RAID 5 was very easy to set up, and since it’s software based it does not require any special hardware and is easily migrated to new hardware in case of failure. This is an important criteria for many home users, since we don’t typically have boxes of identical hardware sitting on the shelf to prepare for failure. Moving to new hardware is incredibly easy. Simply install Windows Home Server 2011, connect your array drives, and import the foreign array under Disk Management. WHS2011 deals with the details. WHS2011 can be installed with everything connected, but be careful to not install windows to one of the drives of the array.
A failure point here is that there is no real way to do online array expansion, so the size you build now is what you have to work with. The drives must also be empty when starting the array and empty when disabling it.
Notification
Since a server is likely going to a box that is rarely looked at directly, I want to have some kind of notification system in place when something isn’t working as it should. A second failure is a weakness of RAID 5, but it can survive the first failure without a hiccup. In this situation, you want to know to replace that first failed drive as soon as possible, which means notifications are essential. Windows Home Server has e-mail notifications for critical events. You must have an SMTP server available. Most ISP’s can provide this, and Google’s free G-Mail has it available as well when POP3 or IMAP are enabled. However, worth noting is that a disk failure in a redundant array only raises a warning. It raises nothing to the WHS2011 Dashboard, and no notification is sent. This, I believe, is an absolute failure. Because of this, third party options or frequent manual reviews will still be required.
Performance
I started initializing this array at about 11pm on a Monday. The array was usable almost immediately, but at reduced performance as it began “resynching”. The array finished resynching sometime between midnight and 10am Saturday morning. In my tests on virtual machines, replacing a failed drive had similar results as far as time to resynch. I am not going to bother testing this on hardware, because I don’t want this machine down for another week. I could even accept a one time hit on initialization and rebuilding, but personally I found the results, especially write speed, far less than satisfactory. A 1Gbps network has a theoretical cap of 128MBps. I have a strong belief that my disk access should not be my bottle neck when a single drive is pushing around 200MBps sequential access. Interestingly, I expected to see heavy CPU utilization during writing, especially considering the results. I never noticed any significant change in CPU activity during read or write operations.
 Resynching |
 Ready |
 Single drive failure |
Verdict
Ease of Use: 4/5, Notifications are lacking.
Drive loss limit: 1
Performance: 2/5
Expansion / Upgrade options: None
Efficiency: N-1
Cost: Free with Windows Home Server 2011.
Viable: No