Please help me choose a NAS strategy

[monkaiboy]

Hi.

I need to upgrade my NAS as I am running out of space on my Terastation Pro 1.6TB. My initial though was just to upgrade to a bigger Raid 5 NAS, something like DS411+II.

Then I read the Smart SOHOs Don't Do RAID article and the various excellent NAS backup articles and have been thinking hard ever since.

I would really appreciate some advice.

First some background on my usage. I use the NAS to store backups from a couple of PCs, and it is also primary storage for all my media files. My current backup strategy is to back up the Nas to a 1.6TB USB hard drive (occasionally). I have now filled this NAS, and am tempted to get 6TB to future proof (although 4Tb would do in the immediate future)

I am looking at 6TB so obviously a single drive NAS would not do the job. However, I could get a 2x3TB NAS, running with no RAID.
For backup, I could initially use both my existing 1.6 TB NAS and 1.6TB USB drive. Then when I have exceeded 3.2TB of data, I could get a secondary 6TB NAS to back up to.

The other option is to get a 4x2TB drive RAID5 NAS (giving 6TB). I could use the same backup approach here. This would of course cost a little more

A rough pricing is as follows (using Synology NAS for comparison, I know there are cheaper options...):

2 Drive, no RAID
DS212+ with 2 x 3TB drive: £770
DS212+ with 2 x 3TB enterprise drive: £840

4 Drive, RAID5
DS411+II with 4 x 2TB drive: £930
DS411+II with 4 x 2TB enterprise drive: £1210


I guess my questions are:

- Is the no RAID option reasonable/sensible or should I spend the extra for the RAID5?
- is it worth spending the extra for Enterprise drives?


Sorry for the long post and thanks in advance for any suggestions.

Kai

 

[Generic George]

I am looking at 6TB so obviously a single drive NAS would not do the job. However, I could get a 2x3TB NAS, running with no RAID.
For backup, I could initially use both my existing 1.6 TB NAS and 1.6TB USB drive. Then when I have exceeded 3.2TB of data, I could get a secondary 6TB NAS to back up to.

Unfortunately, there really is no good simple, comprehensive backup solution at the consumer level. What you describe is basically as good as it typically gets for a small business or consumer, but there are some serious flaws if you are dealing with business critical data.

The main drawback of this sort of backup solution is that they don't have sufficient storage to have a "history" to go back into. So that if you decide that you needed the version of the file from wednesday of 2 weeks ago and not the version from yesterday. You can't go back and get the older version.

You really need several times the back up capacity to have a good depth of history and even then you would want to set aside a full back up at a semi-regular interval so you have a true history going back several quarters or years.

The best thing to do given the budgetary limitations is to identify a subset of the data that you will make extra back ups of on a more frequent basis.

I would probably look into a blu ray burner drive. With a double layer disk, it will hold 50 GB per disk, which should be enough to cover the most important and frequently changed data. Prices are reasonable, $80-$150 for an internal drive and disks are cheap enough $2-$3 per disk.

2 Drive, no RAID
DS212+ with 2 x 3TB drive: £770
DS212+ with 2 x 3TB enterprise drive: £840

4 Drive, RAID5
DS411+II with 4 x 2TB drive: £930
DS411+II with 4 x 2TB enterprise drive: £1210

I guess my questions are:

the RAID5?
- Is the no RAID option reasonable/sensible or should I spend the extra for the RAID5?

If by no raid you mean no Raid 5, yes.

If by no raid you mean Just a bunch of disks (JBOD or each drive is a separate volume) or Raid 0 (treating two drives as a single larger drive of the total capacity) then absolutely not. You WILL eventually have major trouble.

You do DEFINTELY want to be doing at least raid 1 (also called mirrored) where everything is duplicated between the two drives. Any multi-bay nas can do Raid 1. With it, if one drive fails the other can keep on going with no loss of data.

IMHO, I think it is definitely worth it to spend the money for the extra bays given what you want to use it for. Remember you don't have to fill all the bays right off the bat if money is tight. You can simply fill 2 bays and then pick up more as money permits/need expand.

If you do have enough drives, you might want to look at Raid 6, AKA two parity drives, so that you can loose 2 drives and not loose your data. Or raid 5 with a hot spare, where if one drive fails it will automatically rebuild the raid with the spare drive.

Raid 6 has an extra performance penalty over raid 5 since the parity calculations are more complex. However raid 5 has a vulnerable period where a second drive failure would wipe your data, due to there not being any redundancy while the raid is being rebuilt and while it's being rebuilt you get significantly degraded performance.

- is it worth spending the extra for Enterprise drives?

Short answer is no it generally is not worth spending extra for "Enterprise drives", though that might depend on exactly what the regular and enterprise drives you are looking at are. Most, though not all, "enterprise" drives are low capacity, high speed (10k-15k rpm) HD. They do tend to have longer warranties and are probably tested more rigorously, but for the price differential you can usually buy a couple extra drives to have on hand in the event of drive failure (not a bad idea in any case given that your business depends on it).

 

[monkaiboy]

Hi George.

Thanks for your lengthy and detailed reply, it was most useful.

I reckon a 4 or 5 bay unit with Raid5 is probably my best best then for now. The backup history is not too much of a concern for me. Raid 1 would work out a bit pricey for 6TB.

Now to choose a 4 bay NAS...

Thanks again,
Kai