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Slow Speed via USB 3.0 (Windows 7 64bit)
12-04-2012, 12:02 AM (This post was last modified: 12-04-2012 06:30 AM by Horsi.)
Post: #1
Question Slow Speed via USB 3.0 (Windows 7 64bit)
Dear All,

I have a Drobo 5D since a few days and I'am quite satisfied, good software, very good build quality. I'm just thinking about buying 2 additional Drobos.

But the performance is quite low. With 5x3TB WD RED I have only about 40-60 MB/s write speed and about 110MB/s read Speed.

The Drobo is connected to a Renesas PD720202 with the latest drivers and latest firmware. With an external SSD I get easily above 200 MB/s and a 4 TB Hitachi 7200 rpm comes also up to 165 MB/s read speed.

So, is there any hint/possibility to improve speed ?

Many thanks in advance.
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12-04-2012, 09:23 AM
Post: #2
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
As Drobo is block-abstracted device that applies proprietary BeyondRAID block management to achieve its cool storage size flexibility and fault-tolerance, it will almost never be as fast as a "simple" non-fault-tolerant storage device where there is no "data marshal" involved.

In other words, Drobo is a storage middleman, and while the 5D is screamingly fast, a comparison to a simple drive or SSD is apples and oranges.

Beyond that, unless things have changed on the 5D, a newly-set-up Drobo can take a few days to optimize its performance. So you may see increased performance in the next few days after it's done "settling."

110MB/sec is pretty darn fast - my 4-bay Gen 2 Drobo averages only 20 MB/sec! Smile

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
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12-04-2012, 09:42 AM (This post was last modified: 12-04-2012 09:42 AM by diamondsw.)
Post: #3
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
(12-04-2012 09:23 AM)bhiga Wrote:  As Drobo is block-abstracted device that applies proprietary BeyondRAID block management to achieve its cool storage size flexibility and fault-tolerance, it will almost never be as fast as a "simple" non-fault-tolerant storage device where there is no "data marshal" involved.

In other words, Drobo is a storage middleman, and while the 5D is screamingly fast, a comparison to a simple drive or SSD is apples and oranges.

I'd have to disagree there. If the RAID system (whether traditional or BeyondRAID) is working efficiently, you should see much higher performance of an array of disks than a single disk. Multiple disks provide parallel I/O, minus whatever overhead is caused by the abstraction layer. Traditional RAID reached "wire speed" some time ago, meaning it can process data as fast as the drives can serve it up. Since BeyondRAID is implemented in software on a general purpose CPU it's not going to reach that (wire speed implementations are typically custom silicon), but there's obvious room for improvement.

All of that to say that a single drive exceeding performance of an array is just bad. Yeah, we've been living with it for years, but it really shouldn't be accepted as normal - especially from an array with a new processor, more memory, SSD caching, and external connections capable of using that speed.

(Write speed is a different topic entirely, as you actually have to calculate parity information, deal with data layout, etc - but reading data should be straightforward and take advantage of the underlying I/O parallelism).

Drobo 5N | 250GB Samsung 850 EVO mSATA | 2 x 4TB Seagate, 3 x 4TB Hitachi | FS/EXT3 diskpack
Peak performance >100MBps read/write (based on FS disk pack, no jumbo frames, no SSD)
DroboPorts: Plex, Transmission, OpenSSH, NFS, nano, screen, bash
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12-04-2012, 10:21 AM (This post was last modified: 12-04-2012 10:23 AM by Paul.)
Post: #4
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
hi Horsi, have you been putting lots of files onto it since you got it?
it might be still doing some internal optimisations of the data layout.

maybe if you can try it again to see what speeds you get in case it was just doing something at the time, or in case the windows machine was doing something else? (eg new laptops often have a daily auto schedule of o/s checks, auto defrag, doctor software etc etc that can slow things down for a while)
(heh the phone rang while i was replying and by the time i hit send, 3 replies Smile

diamond i think i read somewhere that a drobo also calculates parity "on read" as well, (maybe in an older post with suiteB i think) when he mentioned ideas about data scrubbings)

(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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12-04-2012, 10:53 AM
Post: #5
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
Ack, I'm running on 3 hours of sleep today so I'm babbling.

My point is "simple RAID" is usually going to be faster than Drobo.

diamondw is definitely right that Drobo should not be slower than a single comparable drive, unless you've done something silly like put only a single disk in.

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
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12-05-2012, 09:45 AM
Post: #6
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
I had similar speed issues prior to updating to the new firmware. I was seeing sustained speeds closer to 30MB/sec with 3 WD red drives.

After the firmware update performance went up to approx 250MB/sec read and 175MB/sec write. Numbers are from CrystalMark sequential 1GB test on a Windows 8 x64 computer connected to Drobo 5D via USB 3.

Numbers above were without the mSATA. With mSATA, they were a few percent higher; however I doubt the mSATA helps in the sort of benchmark I ran.

For large sequential reads, these numbers are significantly better than a single direct SATA 3 connection to the same drive type.

This machine clocks a Samsung 840Pro 512GB SSD at over twice the speed of the Drobo 5D, but at significant penalties in size and price.

(12-04-2012 12:02 AM)Horsi Wrote:  Dear All,

I have a Drobo 5D since a few days and I'am quite satisfied, good software, very good build quality. I'm just thinking about buying 2 additional Drobos.

But the performance is quite low. With 5x3TB WD RED I have only about 40-60 MB/s write speed and about 110MB/s read Speed.

The Drobo is connected to a Renesas PD720202 with the latest drivers and latest firmware. With an external SSD I get easily above 200 MB/s and a 4 TB Hitachi 7200 rpm comes also up to 165 MB/s read speed.

So, is there any hint/possibility to improve speed ?

Many thanks in advance.
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12-05-2012, 11:38 AM
Post: #7
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
Now those figures are much nicer Scott!

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
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12-05-2012, 11:53 AM (This post was last modified: 12-05-2012 12:50 PM by Horsi.)
Post: #8
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
No change with the new firmware.

I testet it with Laptop (Intel native USB 3.0) and Desktop. This is really annoying.

I just wrote to the technical support.
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12-05-2012, 12:58 PM (This post was last modified: 12-05-2012 03:52 PM by bhiga.)
Post: #9
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
It might be worth pulling a diagnostic log and submitting it to Drobo support. It's possible that one of your drives might be slowing things down.

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
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12-05-2012, 01:01 PM
Post: #10
RE: Slow Speed via USB 3.0 (Windows 7 64bit)
Thanks for your hint bhiga !

I sent a diagnostic log also to the support.

I will remove 3 drives will have a look it at again.
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