Drobo

B800fs format - volume size

i have a B800fs with 8 4tb WD Reds. When I set it up, I just wanted the the max space without really looking into file system limitations. So I had dual disk redundancy enabled… I always had just about 22tb size volume… but of course, now that it was filling up, I’m “full” at 16tb.

I can’t figure out how to re-format (partition) this back to be two smaller volumes so I can use my maximum space.

hi, i had a look and saw on this page, that 16TB is a limit per volume, and that 32TB is the max capacity:
https://myproducts.drobo.com/article/AA-01124

if you have 8x4 in dual (DDR) mode currently, then that seems to break down as follows:
8 x 4TB = 32TB raw
32 (-4TB & - 4TB for ddr) = 24TB actual
24TB (*0.9 for filesystem overheads) = about 21.6TB available

can i check if you actually have just 1 volume on your drobo at the moment?
while i havent tried this model, i would have thought that there might be 2 volumes, such as the full one at 16TB, and then a 2nd volume (still at max 16TB but actually only having about 5.5 TB available there)

if you really do need the space, you might be able to use dashboard tools/settings, to untick the DDR mode, (in case this triggers any rebuild with flashing lights, please allow it plenty of time to finish, possibly upto a day per 1TB of data that you have, though usually enabling ddr will trigger a rebuild - i havent switched from ddr to sdr myself, and it might be best to check a bit more about whether there is a 2nd volume that can be setup, to allow you some more space, while still being in ddr mode, only because DDR can be very beneficial, especially if you have so much data or so many drives, and if your drives are fairly old, it could come in handy.

I have a similar problem with the same unit. I have partitioned it into 2 volumes. If I upgrade some of the drives to increase capacity, which volume will actually increase?

Is there any way to tell the actual used & available space per volume, either in a Windows, Drobo or aftermarket utility?

Same unit…both volumes have somehow become RO. How can I change that to “normal,” or RW?

[quote=“Paul, post:2, topic:143842”]
if you really do need the space, you might be able to use dashboard tools/settings, to untick the DDR mode, (in case this triggers any rebuild with flashing lights, please allow it plenty of time to finish, possibly upto a day per 1TB of data that you have, though usually enabling ddr will trigger a rebuild - i havent switched from ddr to sdr myself, and it might be best to check a bit more about whether there is a 2nd volume that can be setup, to allow you some more space, while still being in ddr mode, only because DDR can be very beneficial, especially if you have so much data or so many drives, and if your drives are fairly old, it could come in handy.
[/quote]I have some experience with this. I went from 2-drive redundancy to one as an experiment once. The total time it took was less than 5 seconds. Apparently, only a flag is changed and there is no reorganization, rebuild, copying, or indexing needed. In spite of what the Drobo techs said, there was absolutely no disk activity (as determined by lights & sound) afterwards, and I checked repeatedly for days.

However, when I tried to reverse the process and return to 2-disk redundancy, that option was not available in the Dashboard. Keep in mind that the amount of actual data on the drive had not changed by even a byte.

I gradually removed data from the unit, and eventually the 2-drive option came back, so the amount of space required for this to be enabled is different than the maintenance amount. That is, you may have too much data to enable the option, but once the option is enabled, adding more data has no adverse effects.

Re-enabling the 2-drive option (from 1) took 2 weeks while disabling it took 5 seconds. I advise you plan accordingly if you want to experiment.

I guess I was thinking of my formatted space as a single drive partition… as I learned more since this post, I just share another volume and it shows up in windows as 16tb, but I can use up space on that volume and fill up space on another volume up to the capacity of my array.

hi wmsntv, if you now have another volume and can use more space, that is good (though please try to keep an eye on the used space % in dashboard overall, just to try to remain within the 95% used mark, probably at 94% as is best to not overfill a drobo, but also it will remain quicker if it has more than 5% free as well)

thanks sevastopol for your info on your ddr to sdr process,
(i was also wondering where i had heard your name before, and not just for other posts in the past - and finally remembered the last part of the name was a character in a film called Fiddler on the Roof :smiley: