Drobo

How my data is being used

New drobofs, still in the process of copying data to it. On my dashboard, how my data is being used section seems strange. Can you tell me if this is normal?

What is the overhead for? Can’t seem to find out anything on this piece.

3 1.5 TB drives, 4.50 total, 4.09 actual

Currently 2.68 tb available
0 Used for expansion
1.40 tb used for protection
4.89 gb overhead

Thanks for the info,

Joe P

I would assume this is the Linux OS install that’s on the DroboFS.

Most likely not the OS. A quick check using “du -xh /” indicates that the OS takes about 40 MB.

My guess it is related to the management of the disk pack, and used by the underlying BeyondRAID tech.

Very odd that all of the photos of this functionality always have zero for overhead. I have not yet seen any detailed explanation of what this is, should be or what is normal. It would be nice to have this information.

Overhead is generally reduced if you have the same make/model drives with the same storage space on them (this can vary) - and even then, you might end up with overhead.

Thank you all for the input and hypothesis on what this represents. I have all the same type of drives. Frankly I am puzzled in the category of overhead. If it is so murky and not definable (no information on this) I would assume it would be better lumped into the used for protection numbers not separately called out. I will leave it up to Drobo to explain and explain their rational for having a separate category.

You’re talking about less than 5GB on 4TB.

ive also got 4.89GB of “overhead” on each of my drobo v1, and v2 dashboards.

i think it also includes the space you “lose” to formatting of a drive.
eg aside from drive manufacturers selling drives which seem a bit larger then what they are (due to 1000bits vs 1024 bits), you also then lose some of that space when you format it, due to the formatting process so i think overhead includes some of that too

5 x 3TB drives, 19.56 GB of overhead.

z@FrostyWolf- Five 3TB drives?? What’s the largest volume size you can configure there? Still 16TB I think.[hr]

Checking the DroboCalculator.
1TB uses 0.81GB(x=overhead))
Add 1TB, overhead increase to 1.62GB(2x)
Add 1TB, overhead increase to 3.25GB(4x)
Add 1TB, overhead increase to 4.88GB(6x)
Add 1TB, overhead increase to 6.51GB(8x)

The pattern stays the same if using 2TB drives.