Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions

Slow speeds across an office link

Posted on 2014-12-10
Last Modified: 2016-11-23
We have recently been trying to implement a Server 2012 instance of DFS across 2 of our main sites.  The servers are Dell R720xd with Intel NICs installed with all the latest firmware drivers and updates installed.  When the machines were on the same site, transfer speeds where 100-105MB/s transferring between them, however as soon as one was transferred to another site, these speeds have become 1-2MB/s.  The link between the offices is a dedicated 100MB link with a single hop between our 2 main sites; ping response between the 2 sites is between 26ms (empty office) to 35ms (both offices at peak times).  Our other site in London has a ping response of 20-21ms to our Liverpool site and doesn't experience these issues at all; achieving around 9.5MB/s transfer during peak times (it will hit almost 11MB/s when offices are quiet).

We have had our ISP investigate the link between our Manchester and Liverpool sites and can't find anything wrong at all; when we try and transfer a file from our old Netapp appliance (FAS2020) to the other site we achieve a much quicker 6-8MB/s (although it starts at around 2-3MB and climbs slowly).

We tried the various tweaks and policy changes on 2012 (disabling autotuning, rss, tcp chimney offload, bandwidth throttling, SMB signing etc) but to no avail.  So we downgraded one of the servers to 2008 R2 and performed the same steps - unfortunately we still experience the same problems!

I am rapidly running out of ideas here - I thought the bandwidth throttling reg fix would sort our issues, but it appears not; although I had my suspicions that a 30ms ping time would not be classified as high latency enough to throttle back bandwidth.

Can anyone help??
Question by:Amaze_IT
LVL 57
ID: 40490941
One thing that comes to mind is MTU size; you say this is point to point, but are your running a VPN to get that or is it truly a dedicated point to point (which is getting to be rare)?   If so, you might be fragmenting a lot of packets.

LVL 16

Expert Comment

by:Dirk Mare
ID: 40491833
Are you getting those speeds on all portocols?

Can you run speedtest using TCP and UDP?

+ 1 for MTU settings


Author Comment

ID: 40544778
We are not running a VPN between the sites, we are running straight links with acls through our ISP to avoid as much latency as possible (NOT public links!)  i've been through the configuration with our ISP and we have attempted to modify the MTU size on both our servers and through their routers, but the problem persists regardless.

The strange thing is, when we reboot a router (power off) the speed jumps up and then will gradually die off again over a period of 12 hours of so?  Seems to be regardless of protocols
Three Reasons Why Backup is Strategic

Backup is strategic to your business because your data is strategic to your business. Without backup, your business will fail. This white paper explains why it is vital for you to design and immediately execute a backup strategy to protect 100 percent of your data.

LVL 14

Expert Comment

ID: 40548652
Just a suspicion: maybe you have some kind of name resolution problem ? If the machines run into a timeout every time they try to resolve a name that would slow many things down ... that might be i.e. if you have set upü name resolution by DNS and the machines try to resolve with WINS first ... check the preceedence of the name services or put the critical ones into the HOSTS file, which is evaluated first.

There are possibly more trapdoors like that ...

Author Comment

ID: 40563923
I did check with regards to name resolution as a saw a few people mention this as a possible issue; i even went so far as to reinstall and configure WINS across the sites to ensure there was no problem there; then i did the registry key to force the system to use DNS only - all to no avail.  The have AD integrated DNS, each DC is also a DNS server, primary server is the local site, then secondary is always the central site main DNS server.  All looks to be good!  Althought to be honest I did not test the use of HOSTS file entries for the DNS/AD servers as well.  worth a shot i guess..
LVL 14

Expert Comment

ID: 40563931
Maybe a look at the HOSTS file would help .. if there are wrong entries, name resoution would be a hassle.

The HOSTS file is evaluated first ... sometimes anti-malware-tools put many entries in to prevent malware from calling home. If i contains hundreds of entries, checking it could have an impact on name resolution performance.
LVL 14

Accepted Solution

frankhelk earned 500 total points
ID: 40563932
Maybe a look at the HOSTS file would help .. if there are wrong entries, name resoution would be a hassle.

The HOSTS file is evaluated first ... sometimes anti-malware-tools put many entries in to prevent malware from calling home. If i contains hundreds of entries, checking it could have an impact on name resolution performance.

Featured Post

VMware Disaster Recovery and Data Protection

In this expert guide, you’ll learn about the components of a Modern Data Center. You will use cases for the value-added capabilities of Veeam®, including combining backup and replication for VMware disaster recovery and using replication for data center migration.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The reason that corporations and businesses use Windows servers is because it supports custom modifications to adapt to the business and what it needs. Most individual users won’t need such powerful options. Here I’ll explain how you can enable Wind…
A procedure for exporting installed hotfix details of remote computers using powershell
This tutorial will walk an individual through the process of installing of Data Protection Manager on a server running Windows Server 2012 R2, including the prerequisites. Microsoft .Net 3.5 is required. To install this feature, go to Server Manager…
Hi friends,  in this video  I'll show you how new windows 10 user can learn the using of windows 10. Thank you.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question