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Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
11-30-2015, 06:36 PM
Post: #1
Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
Not sure how many others are out there that may have my same issue but I'm hopeful this thread may encourage Drobo to get moving with giving us more than the current 16TB limit on a single HFS+ Drobo volume. I have a program that needs all data on one volume and my IT folks are telling me I've outgrown Drobo due to the Drobo 16TB limitation. I want to stay with Drobo since I've had such good luck with them but for whatever reason they aren't giving us larger than 16TB volumes for whatever reason. Apple's support page specifically shows that volumes are currently unlimited in size with current OSX. Here's a link to the page describing this info. If there are others with this needs can you please add your voice to this thread. Maybe Drobo will get the message. I have about a year left of drive space before I have to make the decision to either stop using the current software or sticking with Drobo. There are lots of others products out there that are similar to Drobo but do no have the 16TB restriction. The software I'm using is one of a kind. Help me make a point with Drobo. Thanks in advance.
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01-04-2016, 03:46 PM
Post: #2
RE: Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
(just linking to your related post)
http://www.drobospace.com/forums/showthr...http://www.drobospace.com/forums/showthread.php?

(btw i have XP home SP2, a Drobo v1 with 2x 1TB/2x 1.5TB WD greens, & a bkp Drobo v2 with the same + a DroboShare: unused)
& a DroboS v2 with 3xWD15EADS &2x1TB in DDR mode on win7, & a drobo5D (all usb)
  • btw i did a sustained (write) operation for about 6 hours, and got 13.2MB / sec ...objection? "sustained" :)
    (16.7MB/s on a v2 & 47-96MB/s drobo-s)
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01-05-2016, 06:56 AM
Post: #3
RE: Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
First, some possible workarounds.
- Is there no way for you to use with software RAID to RAID0 (stripe) multiple 16TB Drobo volumes to get what you need? Here's a page on how to do that on OS X 10.10 and lower:
http://macperformanceguide.com/Storage-R...http://macperformanceguide.com/Storage-RAID0-cre
and here's a third party program:
http://softraid.com/
that replaces the RAID utilities Apple removed from Disk Utility in El Capitan (10.11).
- Can you just make a soft link inside one volume that points to another?
ln -s /Volumes/secondvolume /Volumes/firstvolume/secondvolume
This would give look like secondvolume was a directory called secondvolume at the root level of firstvolume
I'm not sure if either of these would work in your case.

To be fair, the page you link to says that the maximum file and volume size is about 8 exabytes (8 million terabytes), not "unlimited". Ten years ago 16TB was essentially "unlimited" too.

I would imagine there are probably three main reasons for Drobo not to move forward.

One is compatibility, OS X 1.3 through 10.5 can only manage 16TB and I'm sure that there are a few customers back there. If the new 8EB version of HFS isn't compatible then they would have to have two formatting schemes, one for 16TB volumes or lower, and one for bigger volumes.

Second is probably the BeyondRAID system itself. There has to be some kind of map on the drives that tells the system where the data and it's parity/protection copies are stored. Being able to support giant volumes would either need a giant map, increasing the overhead of the system, or to keep the map sizes sensible then the "chunk" size (i.e. smallest unit of protected data) would have to get bigger, leading to more layout inefficiency and again to more overhead.

Third is that it's engineering work, and they have other higher priority things to do. I expect they're making the calculation/gamble/whatever that the very few customers they might lose due to the limitation is cheaper than doing the work and the testing required to make the change at this point. There's little or no advantage in porting it to older products, their CPUs and memory are probably not up to the task and all it would lead to is support calls about rebuild times and slow data access. If they do it, it will be on some new product.

Just my opinions, and you know what they say about those...

Drobo V2 w/ 2x3TB WD EZRX Greens+2x5TB WD EFRX Red , second Drobo v2 with 2x3TB + 2x2TB (all WD Greens) on a Mac Mini i7 with Yosemite.
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01-08-2016, 10:33 AM
Post: #4
RE: Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
(11-30-2015 06:36 PM)danieljcox Wrote:  Not sure how many others are out there that may have my same issue but I'm hopeful this thread may encourage Drobo to get moving with giving us more than the current 16TB limit on a single HFS+ Drobo volume. I have a program that needs all data on one volume and my IT folks are telling me I've outgrown Drobo due to the Drobo 16TB limitation. I want to stay with Drobo since I've had such good luck with them but for whatever reason they aren't giving us larger than 16TB volumes for whatever reason. Apple's support page specifically shows that volumes are currently unlimited in size with current OSX. Here's a link to the page describing this info. If there are others with this needs can you please add your voice to this thread. Maybe Drobo will get the message. I have about a year left of drive space before I have to make the decision to either stop using the current software or sticking with Drobo. There are lots of others products out there that are similar to Drobo but do no have the 16TB restriction. The software I'm using is one of a kind. Help me make a point with Drobo. Thanks in advance.

I have the same concern about the 16TB volume limit on the 5D and if I had known that was the case up front would have looked for a different storage solution.
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11-10-2016, 05:03 AM
Post: #5
RE: Hitting 16TB Limit Anyone Else Want More? Add Your Voice.
(01-05-2016 06:56 AM)Spiney Wrote:  First, some possible workarounds.
- Is there no way for you to use with software RAID to RAID0 (stripe) multiple 16TB Drobo volumes to get what you need? Here's a page on how to do that on OS X 10.10 and lower:
http://macperformanceguide.com/Storage-R...http://macperformanceguide.com/Storage-RAID0-cre
and here's a third party program:
http://softraid.com/
that replaces the RAID utilities Apple removed from Disk Utility in El Capitan (10.11).
- Can you just make a soft link inside one volume that points to another?
ln -s /Volumes/secondvolume /Volumes/firstvolume/secondvolume
This would give look like secondvolume was a directory called secondvolume at the root level of firstvolume
I'm not sure if either of these would work in your case.

To be fair, the page you link to says that the maximum file and volume size is about 8 exabytes (8 million terabytes), not "unlimited". Ten years ago 16TB was essentially "unlimited" too.

I would imagine there are probably three main reasons for Drobo not to move forward.

One is compatibility, OS X 1.3 through 10.5 can only manage 16TB and I'm sure that there are a few customers back there. If the new 8EB version of HFS isn't compatible then they would have to have two formatting schemes, one for 16TB volumes or lower, and one for bigger volumes.

Second is probably the BeyondRAID system itself. There has to be some kind of map on the drives that tells the system where the data and it's parity/protection copies are stored. Being able to support giant volumes would either need a giant map, increasing the overhead of the system, or to keep the map sizes sensible then the "chunk" size (i.e. smallest unit of protected data) would have to get bigger, leading to more layout inefficiency and again to more overhead.

Third is that it's engineering work, and they have other higher priority things to do. I expect they're making the calculation/gamble/whatever that the very few customers they might lose due to the limitation is cheaper than doing the work and the testing required to make the change at this point. There's little or no advantage in porting it to older products, their CPUs and memory are probably not up to the task and all it would lead to is support calls about rebuild times and slow data access. If they do it, it will be on some new product.

Just my opinions, and you know what they say about those...

i would strongly advise against trying to raid thin provisioned volumes - RAID would usually assume that all of the addressable blocks are actually there - and then try to access them.

what you would want is some kind of drive pooling software

aufs/greyhole (linux) , drivepool/drivebender (windows), but i dont know of any mac versions

My Avatar is my Panther Chameleon named 'Leon.

I have a owned a Drobo v1, v2, DroboPro, Drobo 5D, DroboFS, Drobo 5N and DroboPro FS

I currently have a Windows 2016 Server with 8 x 8TB Seagate Archive Drives, 14 x 8TB WD Red and 3 x 8TB WD Gold
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