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Volume 64TB with 14TB of capacity - Printable Version

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Volume 64TB with 14TB of capacity - oforadada - 04-19-2016 07:51 AM

I made a upgrade of my drobo 5D to the last firmware version 3.5.0.
After this upgrade I format my drobo with 5 disk of 4TB anyone. My surprise is when I create the new volume with de Drobo Dashboard tool and only can create one volume of 64TB when my real capacity is 14,35 TB.
How is possible that?
Such Microsoft OS or Mac Os show 64TB available!
I'm not sure where is the problem!!!!


RE: Volume 64TB with 14TB of capacity - Docchris - 04-19-2016 08:01 AM

There is no problem... this is how it is supposed to work

it is called "thin provisioning"

it allows you to add more capacity later without having to reformat

Imagine that your Drobo is a book... and at the start is the contents page (file table). it shows all the pages going up to 64,000 (64TB)... but actually you have only put 14,350 (14.35TB) pages in your book. by having the contents page lie about how big your book is.. it makes it easy to add additional pages in future... so you can just add more storage without having to make a new contents page (reformat!)

RE: Volume 64TB with 14TB of capacity - oforadada - 04-19-2016 09:42 AM

Thank'u for your answer Docchris!

I don't understand well. I know the concept thin provisioning, but I do not want to work with this system. I use the Drobo for backups, and if the SO see more capacity than the real it's a problem for me, because when the process try to write in the Drobo the TB number 15th or 16th, the process will be fail. But our monitoring system don't detect any problem with the storage.

The solutions like TimeMachine or others calculate the incrementals backups referenced with the capacity available in destiny.

Maybe the fast and simple solution for skip this problem it's create a volume from the OS with only the real capacity on Drobo (14,3TB)?

RE: Volume 64TB with 14TB of capacity - Docchris - 04-19-2016 09:45 AM

I dont think you can do that (change the partition using the OS)

Drobo is built to use thin provisioning

there are instructions in the knowledge base on how to create a time machine partition on drobo (support was added specifically for this)


RE: Volume 64TB with 14TB of capacity - Paul - 04-19-2016 02:54 PM

just thinking about this topic, i think there will be a way in the future for a device, such as a drobo, to be able to report a variable value to the operating system, which is the exact and accurate value for max space and free space....

i (think) the reason it hasnt happened yet, is that the main operating systems only accept a fixed value (from the filesystems for each volume) and that they can only refresh if the volume is unmounted and remounted?
(if so, maybe the answer is a change or future update to the operating systems to address this)

personally, i always think its better to get an accurate value, so that there is less chance of overfilling a device, but having smaller volumes could help you with this in the meantime, either via dashboard, or virtually, or just for backups the timemachine volume as docchris mentions.

RE: Volume 64TB with 14TB of capacity - rameeti - 04-14-2017 04:56 PM

(04-19-2016 08:01 AM)Docchris Wrote:  There is no problem... this is how it is supposed to work

it is called "thin provisioning"

While I understand the benefits, how can I make the Drobos that I have work with my video recording security software. My video software asks me how much room to leave so that it does not fill up the drive and it will then automatically overwrite the oldest video based on the amount of room that it believes is available. Unfortunately, I am not able to tell it that I want it to save 44TB of space for other purposes. They didn't imagine that anyone would have a need for that much blank space to be unused. A reasonable assumption on their part.

RE: Volume 64TB with 14TB of capacity - markanderson - 04-27-2017 09:36 AM

I have a similar issue/question. I've had five, 4TB drives (20TB) in my 5D's which gives me a reported, usable capacity of 14.35TB. I now replaced one of the 4TB drives with a 6TB drive in each and I *still* get a reported available capacity of 14.35TB.

This is a problem. We are an all-Mac environment and the Finder shows an incorect available amount of storage, but even worse, the Drobo Dashboard is complaining because it says I am critically low on space even though I just added 2TB to each 5D.

Shouldn't Drobo's own software know about thin provisioning? Or am I missing something?

RE: Volume 64TB with 14TB of capacity - Paul - 04-28-2017 11:31 AM

hi mark, i think once another 6TB drive is added to your drobo (probably by way of upgrading another 4TB into a 6TB), it would then give you an actual increase in usable capacity...

this is because the usual default protection of single (SDR) drive redundancy, essentially uses up the equivalent amount of space, equal to the size of your largest drive, which in this case is 6TB.

if your drobo is currently in a stable state, upgrading 1 more smaller drive into a 6TB should to the trick, and give you just over 16TB i think