Slow network transfer speeds for very large files

Evil-I

Evil-I

Evil-I

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Joined
20 Apr 2003
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Gloucestershire
Hi All,

This is an issue I've been aware of for a while but not really cracked or really understand what the issue is.

So to give you a quick run down.

My company does a lot of video and multimedia work, which means we are often dealing with video at 1080p uncompressed.

Now to give you an example, one little video project which has been supplied as an uncompressed 1080p quicktime from our animators is 30Gbs for a 6 minute sequence.

The problem occurs when trying to transfer files like this over our network. We have a completely gigabit network, using a 48 port linksys switch and a 48 port cisco switch and have no problems with file transfers up to approximately the 3-4Gb individual file size (usually average around the 80 -100 megabytes per second transfer speed).

However when transferring VERY large files the data transfer speed is as expected but quickly falls to around the 8-10 megabytes per second mark.

I'm currently doing this between a Vista 64 machine (using 3Ware RAID5 disk system capable of 200megabytes a second) and a windows 7 64 machine (using 3Ware RAID5 disk system capable of 350 megabytes a second) and its painful. .... We've had similar problems between my vista machine and our Windows Server 2003 R2 data servers.

So whats the issue here? Why such a massive difference in transfer speeds once you get to individual files bigger than 6gb or so?

ANy help much appreciated.

E-I
 
Try a robocopy with the /ETA switch.
Windows explorer is the slowest way to copy files, any command line copy will be faster.
 
been having a look at this post about issues with file transfer speeds.

Its specific to vista, but may be relevant.
 
Showboat said:
Try a robocopy with the /ETA switch.
Windows explorer is the slowest way to copy files, any command line copy will be faster.
Click to expand...

Thanks for this, I'm going to have to wait a bit before i try it, apart from anything else, the file names and paths aren't particularly console freindly currently, lots of long wided file and folder names with spaces etc. I've nearly got one of the files transfered, so short term I'll let that one complete before I try further tests.

I'll make a copy of one of the 30Gb file stick it on the route of a drive and name it something easy then do a cross network test as you suggest.

Thanks,

E-I
 
Not that this is in any way the cause of the slowness issue. But. Turn on jumbo frames on all your NICs and switches. Should see marked increases in throughput for large file transfers and high bandwidth streams.
 
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