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One large, fast volume?
01-13-2016, 02:19 PM
Post: #1
One large, fast volume?
Hi folks, I'm a bit new to the world of Drobo. I just snagged a pair of Drobo 5D devices and five 6TB WD Red hard disks. Put all 5 disks into one device, threw a 240GB mSATA in the bottom of it, plugged it in, and ... created two 16TB volumes. The device is connected to a USB 3.0 card in a Dell PowerEdge R710 II running Windows Server 2012 R2 Standard.

I understand that this is the only configuration supported in the current firmware revision, and 16TB is enough capacity for the next month or two, but are there any plans to increase maximum volume size in the near future? I plan on feeding five 6TB WD Reds and a 240GB mSATA to the other Drobo in the coming weeks, and it would be nice to know how long I'll have to deal with two volumes on an external device instead of one.

Failing that, is there a way to run the unit as a JBOD and create a Storage Space spanning the disks?

Additionally, the write performance of the 5D doesn't seem to be all that great. As I type this I'm pushing a 29.7GB file to it over a 10Gb network at about 85MB/s. I can copy that same file to a Buffalo DriveStation Quad (four 6TB WD Reds in RAID 0) at 130MB/s. The server's direct-attached 6Gbps SAS RAID (36x 4TB NLSAS drives from various manufacturers in RAID 50) can write it at 1.0GB/s; I don't expect the Drobo to reach anywhere near that speed over USB 3.0, but shouldn't it at least match the Buffalo's performance, especially with a 240GB SSD involved? Is there some sort of background initialization process that's hobbling performance?

Sorry if these are very Drobo n00b-ish questions, but I am, after all, a Drobo n00b Smile
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01-13-2016, 02:32 PM (This post was last modified: 01-13-2016 02:33 PM by Docchris.)
Post: #2
RE: One large, fast volume?
The ssd helps reads only

It can't cache writes because it isn't redundant

I'll think about the volume pooling but if you we're going to try that my gut instinct isn't to avoid storage spaces.

Drobos originally only supported ntfs and hfs file systems... Ext3 was added later.

The reason the file system is important is because drobo is file system aware... It's how it keeps tracks of which blocks are in use and which blocks aren't, it isn't just a dumb block level device. So I think trying to layer a virtualised "slab" system on top of a virtualised block system (drobo) would be a recipe for disaster!

You would need to use something like drive pool which uses normal individual NTFS volumes but presents them as one unified storage volume. You wouldn't get a speed up , but you would have one single addressable space

OR you could use drive pool with duplication. No additional space, but you would get redundancy in case a drobo died and also a read speed up as drive pool can read from both drobos at once when reading a file
Oh, and drobo write performance often sucks :/

Although it's not too bad... Simultaneous reads and writes incur a significant performance penalty!

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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01-13-2016, 03:16 PM
Post: #3
RE: One large, fast volume?
Thanks for replying so quickly!

It would be really cool if it could cache writes, especially if a large-ish capacity SSD is present. It would improve performance tremendously for files that are much smaller than the cache. Not holding my breath, of course, but that can be filed under the "would be nice" column.

I've seen layered virtualized file systems in the past, but the underlying technology was a bit different and took that possibility into account. I'm basically using the Drobos to copy a whole bunch of large files off a server and transport them to another location that is a significant distance from here, since that's faster and cheaper than copying them over WAN link.

I noticed an article earlier that mentioned 64TB volume support on the 5N. Is this true? If so, is this something that can be implemented on the 5D relatively easily? Once the files are copied from the Drobo to tape, I'm really not concerned with the contents of the Drobo itself, so I'm more than happy to re-create the volume as specified in that article.
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01-13-2016, 06:38 PM
Post: #4
RE: One large, fast volume?
Unfortunately it cant write cache as it wont allow data to be non-redundant

the 64TB volume on the 5N is a bit differnet to on the D, as the 5N is really a Linux computer addressing a drobo, all in one box. and that was more urgent as the 5N only allows one volume!

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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02-02-2016, 10:06 AM
Post: #5
RE: One large, fast volume?
So, reflecting on my purchase: lesson learned. Drobo was the product that fit the bill at that time, but it's definitely not the solution going forward. I was foolish enough not to do additional research before buying in to the USB 3.0 connectivity (can't saturate the port), mSATA for "increased performance" (read only), and 32TB maximum capacity (2x 16TB volumes).

Would the 5N have been a better choice? In terms of capacity, yes, as it supports a 64TB volume; however, I assume its performance matches that of the 5D, so no, the 5N wouldn't have been any better. Same goes for the B810n, which might just saturate a 1Gbps Ethernet link due to the increased number of drives, but it still needs to be faster.

The B1200i can give me a single 64TB volume, but we have made it a point not to use iSCSI unless it's absolutely necessary. We have site-to-site replication going on between two of our SANs using iSCSI, but all local connectivity is over 16Gb fibre channel. And, as with the B810n, the B1200i only has 1Gb connectivity, so it's a no-go.

Is the Buffalo DriveStation Quad the magical solution to this? It most certainly is not. The only way I can get respectable performance out of it is to configure it as a RAID 0, and we all know that it's called RAID 0 because that's precisely how many files you have left when it fails -- zero. Given that I'm shipping these enclosures to Australia, and that they're shipping them back to me, there is a giant risk of disk failure. That's another thing working against the B810n and B1200i: it'd be pretty expensive to ship them, and the team on the other side of the Pacific would have to do a nontrivial amount of work to get them working.

With that said, I have other solutions open to me:
  • Keep using the DriveStation Quad until it runs out of capacity, at which point I should probably switch to a DriveStation Ultra 10-Drive
  • Get a Dell PowerVault MD1200, stuff it full of 4TB NLSAS drives, create a single RAID 50 volume on it, and ship that back and forth
  • Build a full-tower PC based on a workstation motherboard with 10-12 6Gb SATA ports and 10Gb Ethernet, fill it with 6TB SATA disks, and ship that back and forth.

What would make the Drobo 5D an ideal solution for my purposes?
  1. Allow end-users who know what they're doing to disregard redundancy when using mSATA for improved write performance. If this requires suspension of DroboCare while this option is enabled, fine.
  2. Support 64TB or larger volumes.


Short list, yes, but it would definitely make the 5D a viable longer-term solution for me.

Would it be useful at home? Oh yes. I would use the hell out of this thing at home. But definitely not for work.
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02-02-2016, 06:25 PM
Post: #6
RE: One large, fast volume?
hi, can i check if there is a particular reason causing you to ship physical units from country to country, instead of just the data? are you just trying to make backups and replicate the data across 2 different countries?

btw there was a fairly recent post about 64TB support coming to other models like 5D in future, so if you already have some 5D units, their config options could expand in time too, eg as here:
http://www.drobospace.com/forums/showthr...http://www.drobospace.com/forums/showthread.php?tid=145621&pid=196096

(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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