Author Topic: udp packet loss stats  (Read 3873 times)

peter

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udp packet loss stats
« on: May 07, 2015, 01:34:01 PM »
just information to share
It is only my test
udp start dropping packets(with following iperf cmd):
iperf -c 192.168.4.31 -b 7m  -l 50k -F file ( consisting of random numbers)

Thanks
Peter

ahenning

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Re: udp packet loss stats
« Reply #1 on: May 07, 2015, 02:43:32 PM »
Thanks Peter,

Loss is expected > 6 Mbps on Express. We built in a bit of headroom as you see with the 7 Mbps.

Even though the express limit is the determining factor, could you perhaps add the hardware spec on both ends to put the 7 Mbps benchmark into perspective?

Also, it would be a good test if we could load trial keys to see what the hardware is really capable of.
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peter

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Re: udp packet loss stats
« Reply #2 on: May 08, 2015, 02:21:15 AM »
Testing hardware:
CPU I3
vsphere 5.5
4G memory (assigned to wanos virtual machine)
regular SATA disk

I will do it again with better hardwares and keys because i think bottleneck is express limits.  Key requesting emai
l has been sent.

ahenning

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Re: udp packet loss stats
« Reply #3 on: May 23, 2015, 04:18:01 PM »
Hi Peter,

Looking forward to your updated bench results in the i3?
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peter

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Re: udp packet loss stats
« Reply #4 on: May 25, 2015, 06:53:31 AM »
Sorry to keep you guys waiting.  I have been committing to something else lately.  This week should have chance move back to it.

peter

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Re: udp packet loss stats
« Reply #5 on: May 27, 2015, 07:21:44 AM »
Hi,
Test is with applied keys on I3 by using above mentioned setting.
On high mode
Feeding zipped(tared) data
Once network was over 8Mbit/s, udp started lossing packets.  Loss was  getting much more
obvious when bandwidth was over 10Mbit/s. Initially, I thought that bottle
neck was CPU but it was never over 25% from dashboard when under 20Mbit/s.
Then I guess CPU is not the reason.

Feeding txt data
Milege could go up to 50Mbits, then I guess CPU is issue again.

On low mode
Feeding zipped(tared) data
Bandwidth could reach 90Mbit/s without lossing packets and CPU never went over 10%.
But datastore seemed not working on low mode because it is always 0%.

On both cases, memory were never over 10%, then memory issue can be ruled out.

By using wireshark, I can see both high and low mode compress data.  As
datastore is gone on low mode, I guess datastore io could be the issue
and  searching dedup from datastore also could be the issue because without
datastore bandwidth went up very much.

Questions:

1 Is CPU the issue or not (major or minor)?
2 Is Disk io the issue or not (major or minor)?
3 Is datastore gone on low mode ?

ahenning

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Re: udp packet loss stats
« Reply #6 on: May 27, 2015, 08:07:29 AM »
Thanks Peter, good info

1. Depends which i3? Check the CPU graphs if there is something unusual on one thread.
2. Likely, main site or remote site.
3. No, Low puts the datastore in receive mode. So its compatible with a peer in high.

Questions:
Are both peers the same hardware spec?
What is the HDD spec and rpm?
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peter

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Re: udp packet loss stats
« Reply #7 on: May 28, 2015, 09:02:25 AM »
i3-3240 2core 3.4G
HDD SATA 7200rpm 6Gb/s
Both sides got the same hardware

Question:
I only saw CPU from dashboard
CPU graphs did not show anything

3. No, "Low puts the datastore in receive mode. So its compatible with a peer in high".

Do not understand.  Both datastores are 0% (sending and receiving sides)

ahenning

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Re: udp packet loss stats
« Reply #8 on: May 28, 2015, 10:15:36 AM »
Hi Peter,

The benchmarks are low for the CPU. Is this running in KVM?

This wont affect you, but for interest sake 4 Core CPU's with 8 threads see an improvement in a ptp setup with hyper-threading disabled. If some of the heavy processing falls on the same CPU core, but different threads, the impact can be close to a 50% drop in throughput.

7200 rpm is ok for 10 Mbps in High. ( http://wanos.co/wan-optimization/performance/ )
50 Mbps in high is decent for 7,2K. I take it the data is repetitive, cached in memory and hence disk IO is low.
90 Mbps in low is not good for the CPU, maybe the network is somewhere limited to 100 Mbps? Expecting to see closer to 200 Mbps, unless PLR is enabled?

Datastore will remain 0% if both sides are Read-Only (Low).
« Last Edit: May 28, 2015, 11:36:04 AM by ahenning »
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peter

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Re: udp packet loss stats
« Reply #9 on: May 28, 2015, 02:55:52 PM »
Yes, I just found out my network is 100Mbps.  I need to figure out why two 1G ni
c connection only gives 100M under auto mode.

It is running in vmware esx

One other thing is my disk IO from graph reached between 700 and 800.  What does
it actually mean ?

Thanks