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Isilon ping delay
Hi there ...
Is anybody come across issue like this ?
Issue : it take long time for ping reply ( Isilon --> client ) when using client NAME .. ( not IP )
Note : not all client ... but some client name seems trigger this issue . but Using IP add , it has no issue .
Trace shows DNS has response with no issue , the issue seems inside of Isilon . Means Isilon take time to ask for DNS ...
Would anybody know if there is any information that Isilon take time check DNS ?
or Internal process @Isilon when it needs to name resolution ...
this is it...
① # ping target.domain.local
② PING target.domain.local (xxx.xxx.0.100): 56 data bytes
③ 64 bytes from xxx.xxx.0.100: icmp_seq=0 ttl=128 time=0.240 ms
④ 64 bytes from xxx.xxx.0.100: icmp_seq=1 ttl=128 time=0.386 ms
thanks !
Aya
Stdekart
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February 26th, 2016 08:00
ayas,
Thanks for the question,
There are some fundamental differences on the routing that will occur when using IP vs smartconnectzone name.
Going to IP:
You go out the client interface through any devices (switches, routers, firewalls etc..) between you and node with the IP you are connecting to.
Using smartconnectzone there is a lot more that goes on:
Request goes out client interface going to the DNS through any devices between you and the DNS.
DNS sends a query to the Isilon cluster through any devices between the DNS and the cluster for what IP the client should use.
Based on network configuration on the Isilon Cluster. (round robin, connection count, etc..) Isilon Cluster replies with an IP back to the DNS.
DNS give the IP to the client
And now the connection can commence to the IP supplied.
You also have some internal client cache referencing that is occurring, when using name vs IP. So each ping the client references cache to see what IP to used for that name.
All in all .2 - .3 ms of latency is low for network latency.
Do keep in mind that we only have half of the story here as well, two pings from a single client. We are only able to make assumptions on the data supplied.
Hopefully this covers a general picture of the differences between IP vs smartconnectzone name,
Shane
ayas
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March 1st, 2016 02:00
hi shane!
Thanks you so much for the reply .... so if customer use smartconnectzone name, it would take more time than using IP ... right ? ( generally speaking )
Customer thinks Isilon the one taking time to check name ... not DNS .... ( according to their network trace result ..)
do you think would this be possible ? ( just idea... )
or should i suggest this user to open SR to get checked ?
thanks !
aya
Stdekart
104 Posts
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March 1st, 2016 06:00
ayas,
I would suspect a very minor (hardly noticeable) increase in time and this would be from the client as they would need to check cache to convert name to IP.
What is the time frame for the ping when using IP vs name? I would suggest using a count on the ping of maybe 10-20 to get a solid idea of ping time. Again based on the information the ping the time is minimal.
If needed an SR could be opened up to gather a packet capture from the cluster which is allow us/you to see how long it takes for the reply from the cluster.
IE: Time from once the DNS requests an IP and Isilon reply's with one, which I would expect to be very minimal.
Shane