SOLVED DAS or NAS for backup - your opinion?

[liteswap]

Hi all

I have a FreeNAS server that is working fine as a VM, housing around 12TB of videos and other media. It is currently backed up using a pair of Seagate BlackArmor NAS boxes - which I don't like because they are hard to get under the skin of and are inflexible.

So I planned to pull the eight 3TB drives out of them and build another box using stuff I already have, namely a chassis, PSU and motherboard from an old PC to act as a backup NAS - running FreeNAS, natch. Advantage: flexibility and the ability to site it anywhere the network cable can reach, disadvantage: slower connectivity. Cost: zero.

It then occurred to me that I might do better to build the box as a DAS device, using a SAS expander to hook up to the LSI 9220-8i in the main FreeNAS box. Advantage: mainly faster connectivity due to not having to push data through the network bottleneck, as well as having less kit to manage. Disadvantage: physically tied to the main server, plus more costly.

After some research, I find that it's going to be a bit more complicated than I thought and I would need to find a way to connect to the LSI card - probably requiring more hardware purchases. Cost: £100-200 for the expander and connection to the LSI card.

So my question is: is it worth the hassle factor to build a DAS box or is there some other advantage to doing so that I haven't thought of?

Thanks for your thoughts.

 

[danb35]

So I planned to pull the eight 3TB drives out of them and build another box using stuff I already have, namely a chassis, PSU and motherboard from an old PC to act as a backup NAS - running FreeNAS, natch.

You may want to reconsider that plan, unless the motherboard from the old PC has 16 GB of ECC RAM and a reasonably-modern CPU. FreeNAS isn't really designed to be used on old recycled hardware. I don't have any input on your DAS vs NAS question, but this may factor into it. Check out the hardware recommendations thread for more information.

 

[liteswap]

Dan, thanks for the input. The hardware is about four years old, so not that old, and has about 8GB RAM. I think it'll cope, especially as it's a backup not a live server.

 

[sfcredfox]

I'm not sure if you care about this at all, but in the disadvantages, you said you understood that it would be tied to the main system.

Part of what I expect from a backup system other than just holding another copy of my data is its availability if my main system goes down. If you can't immediately repair and online your main system, your backup data is not available either. If we're talking about your cat video collection, not big deal. If it's data you might want to restore somewhere else, or just have read access to, you're stuck. Just something to think about whether that matters to you.

If you don't care about the lower performance or slow data rates of your backup system, at least it's separate from your primary system and presumably always available. If the data rate is too low to fit into your backup window however, I guess that would be a problem (if you even have to worry about a backup window).

 

[liteswap]

Thanks for the thoughts - in fact you have helped hugely, simply because you remind me that backup is actually about restore. If the main server goes down, DAS is useless. Therefore a second NAS is the way to go - unless I've missed something