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DL385G6 - low performance with USB drive

KSa_3
Occasional Visitor

DL385G6 - low performance with USB drive

Hi all,

I'd like to use an external USB 2.0 hard drive for backup. Unfortunately read and especially write performance is extremely bad.
My configuration looks like this:
- DL 385 G5, SmartArray P410 with 512MB BBWC
- 4x 500GB SAS 7200rpm disks in a RAID5
- external 1TB USB 3.0 hard drive connected to a USB 2.0 interface
- Hyper-V Server 2008 R2

When copying big files from a partition on the RAID to the USB drive the performance oscillates from 0 to 30 MB resulting in just 10 MB/s overall.
Connecting the same USB disk to the USB 2.0 interface on my Windows 7 notebook results in almost 30 MB/s and no oscillations.
Can anybody explain this behavior?
Or even better - can anybody provide a tip how to fix this problem?

Thanks in advance
Klaus
5 REPLIES
KSa_3
Occasional Visitor

Re: DL385G6 - low performance with USB drive

After some more research on that matter it turns out that the problem ist not drive specific - other USB 2.0 drives show the same problem and front and back USB ports perform equally bad.
More importantly: formatting the drive with FAT32 results in a flat 10 MB/s write performance. So there are no oscillations with FAT32 but the same overall performance as with NTFS.
I think the oscillations are resulting from the usage of a write buffer by the OS - NTFS buffered, FAT32 unbuffered.
The problem with the extremely low performance still persists.
Any ideas?
I would be willing to use an extra USB 3.0 card but didn't find one that is being supported on W2k8R2 or servers in general.
Does anybody know of one?

TIA
Klaus
KSa_3
Occasional Visitor

Re: DL385G6 - low performance with USB drive

Hi all,

this seems to be more difficult thant I thought it would be :(
Talked to HP support in the meantime and they say: "USB hard disks are not supported at the Proliant USB ports." and "Only devices in the quick specs are supported".

Wow! It will work with every 300$ PC but I cannot rely on the proper functioning of standard USB 2.0 ports with standard USB 2.0 devices when using a Proliant server!

I can hardly believe that...

Regards
Klaus

Saberus
Valued Contributor

Re: DL385G6 - low performance with USB drive

Klaus,

By default, the AMD-based Proliant servers are set to use USB 1.1

In the RBSU, there's an option to set the external USB to 2.0 under System Options, IIRC. (The internal USB will run at 2.0 regardless)

Why they set it to 1.1 by default, I haven't the foggiest.
Saberus
Valued Contributor

Re: DL385G6 - low performance with USB drive

Also, we have had no problems with USB hard drives in our servers. The server has no idea what's connected to the port, only the OS.
KSa_3
Occasional Visitor

Re: DL385G6 - low performance with USB drive

Hi Saberus,

thanks for the tip.

I noticed the USB config - don't really understand why it's set to 1.1 but reconfigured it to USB 2.0. I think otherwise the performance would have been even worse - as far as I remember USB 1.1 allows just a bit more than 1 MB/s.
"Luckily" I have 10 MB/s.

Of course I expect the performance problem to be the same irrespective of what device I connect to the USB port. The only difference is that HP refuses to care about it as long as it's not an officially supportet external device.

Cheers
Klaus