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Why SAS EG sessions are disconnecting from SAS Server

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Frequent Contributor
Posts: 88

Why SAS EG sessions are disconnecting from SAS Server

Hi There,

 

Is there are some changes on disconnecting the user login from the SAS server?

 

Because SAS EG always disconnecting from the SAS servers, say after a lunch, when come back, the server is disconnected, then users’ work is lost and need to run the whole program again.

Thx-

Ram

Esteemed Advisor
Posts: 6,636

Re: Why SAS EG sessions are disconnecting from SAS Server

Which version of operating system, SAS and Enterprise Guide?

Take a look at the spawner log, maybe you can find a pattern.

It could be that your server system kills inactive processes when under load.

Or you see the results of intermittent network problems (is a VPN involved?)

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Maxims of Maximally Efficient SAS Programmers
Valued Guide
Posts: 3,206

Re: Why SAS EG sessions are disconnecting from SAS Server

It is a rather old issue described at: https://communities.sas.com/thread/2632?start=0&tstart=0

What is happening that low level traffic network, that session is not seeing activity and so it will disconnect that after some time.
As the network is still growing more routers are coming this kind of policy if more often build in. A 2 hour limit is a very common approach. It is checklist point of hardening the network. You will not find anything in SAS or SAS logging as the effect is the same as disconnecting by cutting of the wires.
As you say if often after lunch ...  This is my trigger to think about that.

With SSH this behavior is well known. You have a keep alive setting in the configuration option.
SAS did not have this kind of settings. With 9.4 you will find it. SAS(R) 9.4 Intelligence Platform: Application Server Administration Guide  "keepalive parameter".
There is not good documentation at SAS on this topic yet.

---->-- ja karman --<-----
Esteemed Advisor
Posts: 6,636

Re: Why SAS EG sessions are disconnecting from SAS Server

Yes, that's why I was asking about VPN. When directly connected in our internal LAN, sessions will persist over days without interruption (EG 4.1/SAS 9.1.3).

Have to see how it develops with EG 4.3 and SAS 9.2.

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Maxims of Maximally Efficient SAS Programmers
Valued Guide
Posts: 3,206

Re: Why SAS EG sessions are disconnecting from SAS Server

No improvement with Eg 4.3 9.2 as your need 9.4.  This time-session breaks in routers seen getting implemented internal networks getting them segmented.
Segmented by the office and server-locations and than some madness as trying to isolate developers into network segments, goal isolation of data -production data- on servers. The idea of giving everybody an different desktop according to that environment. Seeing that to happen again as virtualized desktops getting implemented.

---->-- ja karman --<-----
Respected Advisor
Posts: 3,059

Re: Why SAS EG sessions are disconnecting from SAS Server

You should also talk to your IT network specialist. With our SAS BI server setup we had to ensure that any related network traffic with timeout rules needed to be configured to suit our requirements. It may not be just idle TCPIP connections that timeout, we also had the problem of firewall ports timing out as well.

This is way beyond what you as a SAS user might be aware of hence the need to consult the experts. Our experience is that with the right network traffic rules there is no need for the "keep alive" option.

Valued Guide
Posts: 3,206

Re: Why SAS EG sessions are disconnecting from SAS Server

@SASkiwi, yes you are right with these IT network specialists. When the situation is they are external and limited in what they are allowed to do you can get a dead-lock. The firewall with allowing ports/service is a known topic with a SLA.  There are a lot of rules coming in to those guys.

The session time out is coming in with hardening requirements not easy to overrule..  

http://www.cisco.com/c/en/us/support/docs/ip/access-lists/13608-21.html

Session Management Cheat Sheet - OWASP

As the session keep-alive setting is a well known option with SSH (and others) why would SAS ignore that approach?  
Becoming an isolated technical approach is a bad position.

---->-- ja karman --<-----
Respected Advisor
Posts: 3,059

Re: Why SAS EG sessions are disconnecting from SAS Server

Hi Jaap. I totally agree that there may be occasions where a session keep-alive option may be your only solution. For example when you are not in control of the entire network between SAS server and SAS client (cloud computing comes to mind).

Where I work our SAS environment is totally within the organisation's internal network. In this case network traffic rules can be controlled completely including time-out rules. I do appreciate there will be many SAS users whose SAS environments involve networks that are not possible to control completely so the new SAS 9.4 option will be very useful.

Great feedback - Thanks!

Frequent Contributor
Posts: 88

Re: Why SAS EG sessions are disconnecting from SAS Server

Hi Jaap and SASKiwi,

 

Thank you for your reply and its very helpful to understand adn cascade the information with customer team and security team.

 

Network team not agree for changeing the FW interval time out details and TCP/IP Keepalive parameter values.

 

I have suggested the SAS KeepAlive parameter set up can be done in SAS SMC which keep sends the packet once in 50 min(as FW interval timout is 60 min). 

 

But sucurity team doesn't want allow this cause if users didn't logoff SAS EG session before leaving to home, then SAS Keep those session active for whole night like there is no cut off time to stop packet sending from SAS though user session doing nothing.

 

Is there any way to stop sending Keepalive packets to connected EG session for only 5 hours? i hope not possible in 9.4.

 

Is there any way to set up the Keepalive session parameters where SAS EG running at User PC windows 7 enterprise(OS)?

 

Thanks- Ram

 

 

 

Respected Advisor
Posts: 3,059

Re: Why SAS EG sessions are disconnecting from SAS Server

A better approach might be to stop and re-start your SAS Application server services at a suitable time. This will drop all EG sessions that have been left connected. You would need to ensure that this is done at a time that does not interrupt any genuine working sessions.

 

I doubt you can have the Keep Alive feature on a time schedule.

Frequent Contributor
Posts: 100

Re: Why SAS EG sessions are disconnecting from SAS Server

[ Edited ]

Another option is to move any important files in your WORK lib to a persistant location *before* your SAS EG session times out.  This is a bit of a pain, but if storage space is at a premium and the WORK lib has available storage, it may be worthwhile.  For example, if I have a couple of SQL queries that take up to 30 minuntes each to run, I don't want to have to re-run them simply because I had to go to a meeting and my EG session timed out.

 

Here's the procedure:

1.  Use PROC OPTIONS OPTION=WORK in your SAS program to find your work directory.  My ID is j139823.  My work directory is currently:  /work01/j139823/SAS_work657400F40050_bprd01/SAS_work3D9500F40050_bprd01

2.  My SQL results are stored in gv_20160909.sas7bdat and f1_20160909.sas7bdat.  I move my two files from  /work01/j139823/SAS_work657400F40050_bprd01/SAS_work3D9500F40050_bprd01  to  /work01/j139823

3.  My SAS EG session then times out or is closed.

 

When I restart/reconnect my SAS EG session:

1. I again find my work directory using PROC OPTIONS OPTION=WORK.  My work directory is now:  /work01/j139823/SAS_work109701800178_bprd01/SAS_work05F601800178_bprd01

2.  I move my two files, gv_20160909.sas7bdat and f1_20160909.sas7bdat from /work01/j139823 to  /work01/j139823/SAS_work109701800178_bprd01/SAS_work05F601800178_bprd01
3.  I re-start my SAS program(s) at the point after my SQL queries.  My having moved gv_20160909.sas7bdat and f1_20160909.sas7bdat to my current WORK lib allows me to start working as though I had re-run the queries.


It's kludgey, but it works.  I've been able to run one to many analytical steps sucessfully after my EG session has timed out using the above described technique.  If space is at a premium and your WORK lib is where the space is, then this may be of some assistance.

Best regards,

Jim


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