30 March 2007

Windows Home Server's idea of redundancy

Recently, wish my talk about backup strategies, I was looking at Windows Home Server.  One thing that has kind of put me off about it is its idea of doing redundant storage.

Currently, I use the Infrant ReadyNAS NV and love it so far.  It uses "X-RAID", which is basically just RAID5, though they like to sound fancy with X.  It supports 4 drives, and with RAID enabled, you essentially get the capacity of 3 of the drives.  This allows for better cost per GB than some alternatives like RAID1.  But the disadvantage is if you eventually max out your drives, you can't dynamically expand beyond the 4 drives, and it is difficult to remove the drives and replace them while preserving the data.

Windows Home Server's concept of storage is to treat it more like a pool.  You don't have drives, it simply collectively manages the drives, no matter how they are connected (SATA, USB, etc).  With this, you have much better expandability.

The problem is with how Windows Home Server does redundant storage.  You can mark certain shares as ones that will be redundant, so then WHS will ensure that all files are located on at least two drives, so if one fails, it can be replaced and repopulated with the files it stored.  The disadvantage is that this is essentially RAID1, where each file takes up twice its actual size.  But the advantage is that this is only for shares you want to be redundant.  Ones that aren't redundant will only take up 1x the space.

This makes sense and sounds pretty good, but then I was thinking about something.  Why would I put a file on a network share that I don't to be redundant?  Think about it... lets see what is on my network share.  System images?  Don't want to lose those.  Saved photos?  No, definitely don't want to lose those.  Archived documents?  Nope.  Financial data?  No. MP3s/videos I've downloaded or purchased?  Nope.

If you are going to bother with putting a file on a network share, where it is accessible, but not highly accessible (it is there when you need it, but network shares take a hit on performance vs. local)... why would I put it on a network and not want it redundant?

Overall, Windows Home Server looks attractive for its PC maintenance functions and expandability, but not really for data reliability.  Perhaps the better option would be a Windows Home Server married to a service like Mozy.  Though that may require another PC to be on to send the data.

Posted 9:13 pm | Archive

Comments

Kevin on 3/30/2007 at 9:37 pm

I've been meaning to post about my experiences with Windows Hom Server, but you beat me to it. =)

Actually I like the WHS approach to redundancy better than RAID.  You were wondering what you put on a network share but not make redundant, and a good example of this was in one of the WHS blogs.

The answer is very large files that can be recreated, but with effort. The example given was ripping some of the DVDs that you own for easier viewing (via Media Center or something like that) and to protect the physical discs from getting worn/scratched. They are really large files and wouldn't want to waste disk space by saving them on two drives, because worst case you could simply re-rip them from the physical media.

Eric A. Duncan on 4/04/2007 at 9:16 am

Yep, I read about that as well and it had me wondering.  

But I planned my data storage a long time ago, and it doesn't look I'll deviate from it anytime soon with WHS' solution.  So I'm happy, and upgradable:

* Areca ARC-1220 PCI-Ex8 SATA 9-port card

* 3xWD 500GB HDDs (1 TB to start)

Actually just ordered all of that yesterday.  Woot!

After I start encoding my DVDs (400+), I'll need to upgrade to 2TB sometime to fit them.  Then, SELL THE DVDS!  Tired of storing them.