Slowness for the server

rahul · ‎03-31-2017

Hi Team,

Recently we have migrated some scanner machine from one location to other, and now users are reported for slowness issue while scanning and uploading documents to server.

Could you please suggest or guide me.

Details are below.

Before migration:

Users are connected with in LAN and there is 1 ms latency b/w scanning machines and server. users are able to scan and upload 50 Pages of document (Size 1.58 Mb) in 3 mins.

After migration:

Geographical distance b/w source machine and destination server is around 270 kms and observing latency 12 ms and have checked whole path there is no issue observed (CPU utilization and congestion of link comes in trace logs). and now users are scanning same 50 Pages of document (Size 1.58 Mb) in 15 mins.

Is this normal behavior ?

if yes how can we convince to users

If not, what other possibilities we can check and get better result.

How can we relate latency and delay while uploading documents on server?

Dan Lukes · ‎03-31-2017

Is this normal behavior ?

No one know. It depend on so many details you considered not to disclose.

Capture a session, then analyze captured data with a tool (Wireshark, for example). It may disclose cause to you.

But as a blind shot - some network protocol has been designed for local network and they are unsuitable for remote links. I have protocol between scanning station and server in the mind. If both station and server supports multiple protocol, select the one designed for remote links. But remember - I'm just guessing the cause. It's possible the cause have no relationship to protocol used ...

Joseph W. Doherty · ‎03-31-2017

Very likely the "slowness" is caused by the additional latency.

Often there's not a great deal you can do. There are WAN acceleration appliances, but "your mileage may vary".

A couple of things to check, if hosts are on different networks, insure your hosts have PMTUD enabled. If not, you might be sending packets no larger than 576 bytes. Also insure hosts receiving bulk data have an RWIN sized to support your path's BDP (bandwidth delay product).

Austin Sabio · ‎03-31-2017

Verify your WAN bandwidth traffic is within acceptable bounds -during off hours- this is simply stating your circuit is clean -assuming all applications/services are affected-, identify your point-to-point communication and perform a throughput test. Otherwise, it might be related to the upgrades/changes on the scanner/server side.