PCOIP USB Redirection Detection Slow

[duhaas]

Running with view 5.1 and zero clients from LG and samsung.  Has anyone noticed a long delay after plugging usb stick in for it to show up in windows. It appears it has something to do with the size of the stuck, for example a 16GB stick takes 15 seconds, and a 32 GB stick takes almost 40 seconds.  Thoughts??  Grabbing logs to go over, will post if i notice anything relavant.

[Linjo]

Just to pitch in and be able to compare, what firmware are you running and how long does the same operation take on a Windows client?

Lan or Wan? Latency?

// Linjo

[duhaas]

Thanks for the feedback, I've actually created a ticket with Teradici to see if they can provide any insight.  I did some tests with the software view client as well, and although the performance was improved over the zero client, its still not up to par with what you would see in the physical world.  Just trying to help set expectations for the customer and have not seen anything to indicate there is an actual problem, which leads me to wonder if this is just the expected behavior

Anyone have any feedback in terms of how long they see a usb stick from showing up in windows gues after plugging it in?

[Linjo]

what firmware are you running and how long does the same operation take on a Windows client?

Lan or Wan? Latency?

[mpryor]

How is the stick formatted? I believe Windows always scans the filesystem when plugged in and it's FAT32, which will mean this will take a bit of time for large drives. You see this happen even on a local system, but of course USB latency is orders of magnitude lower (USB only, no network) and so not as noticable. Aparently exFAT doesn't have the same behaviour, though switching may affect compatibility with other operating systems.

[keeggib]

duhass,

I've seen Intel Atom-based thin clients running Windows 7 delay within those time parameters when 16/32GB USB 3.0 thumb drives are directly, physically connected to the thin client.

I suspect that you're just running up against a wall about how fast your remote Windows VM can recognize and dynamically deploy the USB 3.0 drivers for your particular memory stick as well as scan/mount the 16/32 GB volume.

Your issue probably has little relation to latency involving PCoIP USB Redirection traffic...I think.

Cheers!

Keegan

[duhaas]

After creating a ticket with VMware and further investigation, NTFS formatted sticks have zero issues, its all FAT32, VMware has confirmed this to be expected behavior and are going to be esclating my cast to development to see what improvement can be made on the FAT32 side

[mpryor · Accepted solution]

As keeggib mentioned a lot of what you're seeing is Windows' behaviour and the limits of standard USB device performance when redirected. Windows will always read the entire file allocation table for FAT32 formatted drives when plugged in, this means a sector-by-sector request back to the device for that data (each one incurring a round trip delay due to network latency). For NTFS, Windows does not read the whole thing, hence the quicker load time.

[duhaas]

Thanks for the great feedback Mike.  Its the best description to date of whats taking place.  I will update the forum should vmware come back and indicate any type of enhancement to help reduce that time, but your right, it might at the end of the day be a "it is what it is"

[mpryor]

No problem. It was pointed out to me that you can also see some improvements here by reformatting with a larger cluster size (I think the maximum which will be compatible everywhere is 64k). If you do this then you'll have a larger overhead for very small files (both in terms of space used and data sent over the wire), but the total number of requests will obviously decrease for any given size beyond that, so the performance will improve for first scan during plug-in and for large files being transferred.

[duhaas]

Hope this helps, official response from vmware:

Hello Duane,

This mail is with regards to this support request   12222985309.  Thank you for taking up my call.

It was great working with you on this support request . I will be proceeding to close the support request tomorrow end of day. If you have question you can always use reference of this support request in future for this issue.

Issue description :  Loading of  USB drive formatted with FAT32 takes longer time when used with virtual desktop.

Findings : Just to let you know the VMware engineering team is aware of this issue, will be working to fix it in future release. As of now there is no ETA.

We recommend using NTFS or FAT filesystem on USB drive.

Here is KB article you can use to subscribe to keep you updated.

http://kb.vmware.com/kb/1022836

If you have any negative experience on this support request prior to working with me please provide feedback to my manager. Please find the detail in my signature.

Thank you for choosing VMware

Best Regards,

Mohammed Emaad

Technical Support Engineer | VCP 3 /4/ 5 | Global Support Services VMware Inc.