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I noticed an intermittent slow response on the ping from my application server to my database server. So to diagnose, I tested using a standard ping and Telnet tests.

For the telnet tests, it was able to connect. However some telnet took longer to connect than others.

For the ping, I noticed that I am missing a lot of icmp_seq. It was skipping occasionally. On the other server, it was communicating very sequentially.

But for the app to web and app to app, there were no skipped items. From the app to DB there is.

Anyone have any idea on what is happening ?

Just to add, the database response was very intermittent as well. Sometimes slow. The application server and database are on different network segments as well.

What can we look at ?

  • What OS is on your database server? – longneck Nov 3 '16 at 18:40
  • Aix as well. Thanks. The icmp_seq on the ping from app server to database server skips a lot. – grassbl8d Nov 3 '16 at 18:41
  • What troubleshooting have you performed? How is the state of the network between these servers? How is the load on the servers? Are there any errors in commonly used logs? – Mark Riddell Nov 3 '16 at 18:41
  • The servers are newly commissioned servers with no usage at all. We did thread dumps in the java application to check the slow response and found out that database response is slow. – grassbl8d Nov 3 '16 at 18:42
  • So we did telnet and ping tests. Telnet takes time to connect intermittently. Same with the skipped icmp_seq – grassbl8d Nov 3 '16 at 18:42
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this sounds an awful lot like you have a duplex mismatch or congestion somewhere in the network between the app and the DB. Have you tried doing a traceroute between the 2 endpoint or are they in the same IP subnet? Can you elaborate on the type of network (e.g. LAN,LeaseLine) and available network-bandwidths between the app and the DB?

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  • What do you mean duplex mismatch ? When does this occur ? I'll try traceroute. This is LAN and on different subnets. App and DB are on different subnets. Thanks – grassbl8d Nov 3 '16 at 23:18
  • Is this related to my missing ICMP_SEQ during ping ? Thanks. – grassbl8d Nov 3 '16 at 23:23

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