Adding Drives - When and Why

I have a Drobo 2nd Gen with 2 X 1.5TB WDEARS drives (600 GB data)

I am about to gain 2 more drives 2 X 2TB Seagates (good deal)

My question is what is BEST PRACTICE in adding extra drives? Not the act, but the why and when.
Is it to add both of the extra drives at the same time and load up the Drobo?
Or is it best to only add one drive at a time until the Drobo requires more space?

Am I better off with ALL 4 drives in the Drobo, or do I load it to 3 and leave one in the cupboard just
in-case there is a drive failure and I then have one spare on hand?

if you dont need the space, personally i would add one more drive, to give you 3 total, and as long as drobo doenst give you low space warning, just hang on to the 4th drive in case one of your three drobo drives fails.

Thanks for the response. I gather this is the consensus.

Agreed. I see no reason to add a fourth drive that you know will not be used. It’s just one more drive for the drobo to power and spin up/down. Putting needless wear and tear on a drive that can be kept out until needed.

it also means that WHEN (not if :P) one of your existing 3 drives fails, you can immediately replace it, minimising your at risk time :slight_smile:

So then under this theory is I already have
1.5 + 1.5 = 1.4 usable

So I now only increase by 1 drive only and go to
1.5 + 1.5 + 2.0 = 2.7 usable

So IS the next step to gain space when needed - Replace a 1.5? and go
1.5 +2.0 + 2.0 = 3.2 usable

…And then keep a 1.5 as a spare or do you recommend just to add the forth drive at that stage.

It is just interesting to see what people think in regards to the Drobo and Drive management.

You’d get much more value by adding a fourth drive at that point.

Agreed, use the drives you have

The only reason we suggested keeping your other one spare is because you already have it, well… Spare :wink:

Cheers Guys. All makes sense.

No probs!

I can remember having these dilemmas…

Now im trying to figure out how to squeeze a 9th drive into my 'pro :wink:

I’ve been reading the thread with mixed response.
I think you have received some good advice.
My opinion, I would add the 4th drive. Or sell it. Otherwise, it is just laying around. Make your dashboard pie bigger and greener.
Your amount of data you have today, is it going to grow anytime soon? Do you plan on it?

I purchased a Drobo because I was exhausting 1TB and 1.5TB external drives, needing 2 of each. One for data, one as a mirror.

If I had the 8 drive unit, then I would hold some extra on hand.
Within your current setup/needs, I can see you using only 3 disks. If one fails, then your Drobo can still protect your data on the remaining space.
How long, realistically, will it take you to get another HD?