From the Isilon's side, the round-robin is "perfect", each query returns a different IP, with a TTL 0 = supposed to be uncachable.
It's those DNS servers in the middle, and some clients (OS, but also down to the apps) that might cache even "uncachable" replies, at least for one second or so. Check the docs for the systems involved at your site, in particular for Windows Server DNS...
It's a known bug from Windows DNS delegation. The cache is 1 sec and cannot be remove with ttl=0. You can setup a linux DNS to bypass that bug. At this time, we didn't find a better solution with fast multiple connection to a Isilon cluster.
I thought the Windows DNS is no longer involved on the way back. And I did not know the 'bug' with the lowest TTL of 1s. I suspected the Windows DNS is configured with a TTL of 0.
What other solutions are possible without setting up an Linux DNS?
Can I configure the Client (Windows) to use the SmartConnect DNS only for a few hostnames (= the SmartConnect Names) and for all other name resolutions the normal Windows DNS? The rule would look like:
all addresses except xxx.isilon.xxx >> ask Windows DNS
Peter_Sero
4 Operator
•
1.2K Posts
1
January 15th, 2015 09:00
From the Isilon's side, the round-robin is "perfect", each query returns a different IP, with a TTL 0 = supposed to be uncachable.
It's those DNS servers in the middle, and some clients (OS, but also down to the apps) that might cache even "uncachable" replies, at least for one second or so. Check the docs for the systems involved at your site, in particular for Windows Server DNS...
hth
-- Peter
Peter_Sero
4 Operator
•
1.2K Posts
0
January 15th, 2015 10:00
Yep... remembering the old thread
https://community.emc.com/message/799454
arichard1
21 Posts
1
January 15th, 2015 10:00
It's a known bug from Windows DNS delegation. The cache is 1 sec and cannot be remove with ttl=0. You can setup a linux DNS to bypass that bug. At this time, we didn't find a better solution with fast multiple connection to a Isilon cluster.
philippspohr
1 Rookie
•
107 Posts
0
January 16th, 2015 01:00
Ah, thank you very much. My mistake.
I thought the Windows DNS is no longer involved on the way back. And I did not know the 'bug' with the lowest TTL of 1s. I suspected the Windows DNS is configured with a TTL of 0.
What other solutions are possible without setting up an Linux DNS?
Can I configure the Client (Windows) to use the SmartConnect DNS only for a few hostnames (= the SmartConnect Names) and for all other name resolutions the normal Windows DNS? The rule would look like: