Drobo

changing hard drives in drobo!

hi
i am not sure whether im posting this in the right place or not so sorry if its in the wrong place
anyways my question is that i have 2 drobos and i have 4 1 G.B hard drives in each of them. now i have bought 2 G.B hard drives and i want to replace one of my 1 G.B hard drives with a 2 G.B hard drive…my operating system is windows and since it cannot recognize anything more than 2 G.B, it recognizes each drobo as 2 partioned hard drives each with 2 G.B…now i was wondering if i should just replace the 1 G.B with a 2 G.B hard drive or i should do some stuff in advance…

i’d appreciate it if someone could help me out

thanks a lot

you are fine to just replace a single 1tb drive with a 2tb drive, and wait for it to rebuild.

MAKE SURE - that your drobo is showing all solid green lights and that dashboard shows “your data is protected”.

then you can simply remove a single drive, and insert your 2tb drive in its place.

Personally i prefer to do this with drobo turned off - then when it powers back up it will start to rebuild onto your new drive (this should take about 48 hours).

The reason i prefer to do this powered down is that it minimises the risk of accidentally unseating a second drive while swapping disks out - but you should be perfectly safe to change a SINGLE disk while it is running if you prefer.

Let us know how you get on.

I hope you have used the Dobo Capacity Calculator. http://drobo.com/resources/drobolator.php
You will not get any more usable space when just changing one drive. The largest drive in the pack is used for parity.

he said 2 GB (means TB i can only assume!) hard driveS (i.e. plural)

and the largest drive isnt used for parity - its distributed across all the drives.

But the usable space on a drobo is indeed the total space, minus the capacity of the largest drive.

In a normal raid parity is distributed evenly at all drives. Who knows what DRI does? Regardless, it is much easier to explain it as “the largest contain parity” because it gives an intuitive understanding why part of the largest can’t be used.

If data is equally distributed across all the drives in ta typical RAID environment, it would make sense that if you have one drive that is larger, the Delta is unusable. In most RAID environments, your not allowed to have drives of different sizes for that reason. What it looks like DRI did was took away the rule for same size drive requirements, but the rule of data protection is still there, hence if you have one drive of an odd/larger size, that larger portion doesn’t get used. If you keep your drives in equal sizes, you can have different size pairs in the same Drobo.

For example, go look at the DroboCalcuator and plug in 4 x 1TB drives and you will see that you have 2.7TB of usable space. Replace on of the 1TB drives with a 2TB drive and you still have only 2.7TB of usable space. You’ll notice that the unused “Re3served for expansion” portion is almost 1 TB (the Delta of the 2 TB drive). Now upgrade a 2nd drive to 2TB and you will now see your Available space grow to 3.6TB and your unused goes back to 0.

@ stb - you could just say because the “extra” bit cant be mirrored anywhere? (if you are trying to dumb ti down - dont even bother mentioning parity)

@Microxot - im not quite sure what your point is (if indeed you have one?)

especially since neither of you are really helping the original poster at all at this point.