Why does “vserver cifs session show” show sessions with long-running idle time?

Applies to

ONTAP 9

Question

Why does vserver cifs session show show sessions with long-running idle time?

Answer

• If the client has the IPC$ share AND one or more shares open on the same session then the session will not idle out. 'cifs session show' prints out both a connection ID and a session ID for each session.
  • When a CIFS client sets up a TCP connection to the vserver it will correspond on the vserver side to a specific connection ID.
  • The client then will perform a session setup to authenticate itself and a new session with a session ID is created.
  • The client may choose to set up another session on the same connection. This is common, and is to combine CIFS sessions on top of a single connection.
  • A client may use a single session to open multiple shares and commonly this includes the IPC$ share.
  • If the IPC$ share is the only share open, then it will timeout after 15 minutes assuming the session is idle.

Additional Information

Lab Example:
Munich::*> date;vserver cifs session show -node Munich-01 -vserver cifstomo -fields node,connected-time,shares,idle-time
Node      Date                    Time zone
--------- ------------------------ -------------------------
Munich-01 Mon Aug 15 18:55:30 2016 Japan
Munich-02 Mon Aug 15 18:55:30 2016 Japan
2 entries were displayed.
node      vserver  session-id connection-id shares connected-time idle-time
--------- -------- ---------- ------------- ------ -------------- ---------
Munich-01 cifstomo 1          2742712655    2      "26m 51s"      "26m 32s"
 
In this particular test the shares opened with IPC$ and “test” each corresponding to a different tree ID as seen in a packet trace.  Because the IPC$ share and 1 additional share are open, this session will not time out.
 
Once the client disconnected from the share “test”, the number of shares connected to drops down to 1 (IPC$):
Munich::*> date;vserver cifs session show -node Munich-01 -vserver cifstomo -fields node,connected-time,shares,idle-time
Node      Date                    Time zone
--------- ------------------------ -------------------------
Munich-01 Mon Aug 15 18:59:23 2016 Japan
Munich-02 Mon Aug 15 18:59:23 2016 Japan
2 entries were displayed.
node      vserver  session-id connection-id shares connected-time idle-time
--------- -------- ---------- ------------- ------ -------------- ---------
Munich-01 cifstomo 1          2742712655    1      "30m 45s"      3s
 
The client can confirm the shares it has open by using the “net use” command:
C:\>net use
New connections will not be remembered.
Status      Local    Remote                    Network
-------------------------------------------------------------------------------
OK                    \\10.128.209.152\IPC$    Microsoft Windows Network
The command completed successfully.
 
About 15 minutes later the session idles out as the client has only 1 share open (IPC$)
 
Munich::*> date;vserver cifs session show -node Munich-01 -vserver cifstomo -fields node,connected-time,shares,idle-time
Node      Date                    Time zone
--------- ------------------------ -------------------------
Munich-01 Mon Aug 15 19:14:32 2016 Japan
Munich-02 Mon Aug 15 19:14:32 2016 Japan
2 entries were displayed.
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