+ Post New Thread
Results 1 to 8 of 8
Windows Server 2008 R2 Thread, IPv4 Checksum Offload in Technical; Hello all, At one site I support I've setup a couple of 2008 R2 servers and joined them to an ...
  1. #1

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,345
    Thank Post
    242
    Thanked 1,602 Times in 1,278 Posts
    Rep Power
    346

    IPv4 Checksum Offload

    Hello all,

    At one site I support I've setup a couple of 2008 R2 servers and joined them to an existing 2003 domain. When transferring a 2GB file from 2003 to 2008 R2, the speed is pretty decent, however 2008 R2 to 2003 is extremely poor. I'm talking 2.5MB/s poor and the servers are connected at gigabit.

    I've upgraded the Intel drivers on both 2003 and 2008 R2 servers and this did improve transfer speeds slightly, but they were still far too slow.

    On the 2008 R2 servers, I then disabled IPv4 Checksum Offload and transfers from 2008 R2 to 2003 are considerably quicker and a lot more acceptable. Any idea(s) why this is happening? Is there anything else I could/should tweak? Many thanks!

  2. #2

    SYNACK's Avatar
    Join Date
    Oct 2007
    Posts
    11,271
    Thank Post
    884
    Thanked 2,749 Times in 2,322 Posts
    Blog Entries
    11
    Rep Power
    785
    Could be screwing up the adaptive windowing, hd that alot with Vista to XP

    Clint Boessen's Blog: Windows 7 Slow Access to Network Shares

    netsh interface tcp set global autotuninglevel=disabled
    It flares up under some network conditions when talking to older hosts. Lots on linux based NASs had issues with this and it this fix speed it up by around 10MB/s

  3. #3

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,345
    Thank Post
    242
    Thanked 1,602 Times in 1,278 Posts
    Rep Power
    346
    It's interesting because I've migrated many sites to 2008 R2 and 7, keeping 2003 and XP clients working together during the migration. Not once have I seen this behaviour.

    As soon as clients are imaged to Windows 7, the problems go away. I've migrated the majority of workstations to 7, with only a handful left on XP. Still frustrating Microsoft haven't really made it 'properly' backwards compatible.

  4. #4

    SYNACK's Avatar
    Join Date
    Oct 2007
    Posts
    11,271
    Thank Post
    884
    Thanked 2,749 Times in 2,322 Posts
    Blog Entries
    11
    Rep Power
    785
    As I say, it is only in very certain setups that it happens, it can be to do with network hardware, software/firewall stuff etc. I also have had many sites where this has not caused an issue but two places where it did, one with an SBS server and the other with a Seagete Blackarmor NAS. Both of these benifited massivly from the above reconfig. Never really figured out why it affected those sites and not others but they were much smaller than most of my sites so it was quicker to just fix it.

  5. Thanks to SYNACK from:

    Michael (25th June 2012)

  6. #5

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,345
    Thank Post
    242
    Thanked 1,602 Times in 1,278 Posts
    Rep Power
    346
    This is just it, why some sites and not others. I can only conclude it's something to do with the NIC, the motherboard chipset or something else, rather than drivers.

  7. #6

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,345
    Thank Post
    242
    Thanked 1,602 Times in 1,278 Posts
    Rep Power
    346
    Also - I forgot to add, once you had migrated everything to 2008 R2 and 7, did you switch IPv4 Checksum Offload back on, on the servers? Or leave it switched off?

  8. #7

    SYNACK's Avatar
    Join Date
    Oct 2007
    Posts
    11,271
    Thank Post
    884
    Thanked 2,749 Times in 2,322 Posts
    Blog Entries
    11
    Rep Power
    785
    Quote Originally Posted by Michael View Post
    Also - I forgot to add, once you had migrated everything to 2008 R2 and 7, did you switch IPv4 Checksum Offload back on, on the servers? Or leave it switched off?
    I switched it all back on apart from machines that were running deep packet inspection like ISA/TMG or certain intel cards under Hyper-V untill the drivers got better.

    2003's TCP offload support was a bit hash even with the chimily support - or whatever they called it - there were equal odds of it being iffy in some situations.
    Last edited by SYNACK; 25th June 2012 at 12:25 PM.

  9. #8

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,345
    Thank Post
    242
    Thanked 1,602 Times in 1,278 Posts
    Rep Power
    346
    @SYNACK - I've just come across this utility which turns MSI-X off. I'm going to give it a try later, as I'm still not convinced I'm getting the best speeds.

  10. Thanks to Michael from:

    SYNACK (14th December 2012)



SHARE:
+ Post New Thread

Similar Threads

  1. [Suse] Open SUSE 11.4 repositories failing checksum
    By CHR1S in forum *nix
    Replies: 6
    Last Post: 4th November 2011, 03:10 PM
  2. MD5 Hash (Checksum)
    By Steve21 in forum Windows
    Replies: 5
    Last Post: 10th July 2011, 08:06 PM
  3. Last batch of IPv4 given out
    By Little-Miss in forum General Chat
    Replies: 14
    Last Post: 5th February 2011, 09:47 PM
  4. IPv4 vs IPv6
    By timbo343 in forum Wireless Networks
    Replies: 8
    Last Post: 26th May 2010, 02:08 PM
  5. Move DC to new IPv4 Range
    By Gatt in forum Windows
    Replies: 12
    Last Post: 25th August 2007, 03:50 PM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •