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kungpow
Enthusiast
Enthusiast

VMware ESXi 5.5 U2 - TcpAckFrequency

Looks like there is a bug in VMware ESXi.

Exchange 2013 SP1 on win2k12 r2 on a physical server: no slow upload issue with Outlook.

Exchange 2013 SP1 on win2k12 r2 on VMware ESXi 5.5 U2: has slow upload issue with Outlook.

-tried E100E & VMXNET3 network adapters, doesn't fix the issue.

-only way to fix the slow upload issue is to modify the registry key TcpAckFrequency on the PC

How do I fix this in ESXi without modifying TcpAckFrequency in the registry on the PC?

Thanks

45 Replies
OT_FH
Contributor
Contributor

Hi all,

we are also struggling with that issue in 5.5, thinking about downgrading vmWare Tools to 5.1U1.

Any news that could prevent us from downgrading?

BR,

Oliver

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Magamus
Contributor
Contributor

So we ended up downgrading to a lower version to fix this for now.  It's been working great for us until we upgrade to 6.0 in the near future.

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JozefHu
Contributor
Contributor

Is this problem solved in the newer version? Did anybody get a satisfying reply from VMWare? I disabled TCP Segment Offloading as suggested earlier in this topic but this didn't work. It's not an option to remove the vShield driver. Downgrading is an option but not one I would like to suggest to our customer.

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dfahy
Contributor
Contributor

I am still seeing a noticeable difference in performance on
host 6.0.0, 5224934
vmtools 10.0.9

using vmxnet3

exchange 2016, windows 2012r2, windows 7 clients.

messing with the ack on clients does resolve it but not something we want to engage in.

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Exch2016
Contributor
Contributor

We have Exchange 2016 and Outlook 2013/2016 running on ESXi 5.5 (we also use VMware tools component "guest Introspection" for antimalware protection)

I see some performance issues for Outlook shared mailboxes (running in online mode) and also for a MAPI/HTTP based E-Mail archiving solution.

I suspect that the TcpAckFrequency reg key or the VMWare Tools downgrade may fix it.

However, performance testing is very subjective if you don't have a tool or counter.

How do you measure the performance objectively before/after a modification?

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todd4
Contributor
Contributor

Has this been resolved in newer versions? Also If not we are on 5.5 U2 how do i downgrade my exchange servers to a working vmtools version? They are all on 9.4.10 build 2068191

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