Hi All, I would like to know if this is possible and if possible what is the complexity. Consider a CIFS client, SAMBA Server1 and Samba Server2. Say a session is established between a CIFS client and SAMBA server1. Is it possible for the SAMBA server1 to transfer/redirect/reestablish the connection to SAMBA server2 without the CIFS client knowing about this? The session between the CIFS client and SAMBA Server1 should be closed and a session between CIFS client and SAMBA server2 should be opened both transparent to the CIFS client. Thanks for any help/suggestions. -Siva
"Sivaselvam, CN" wrote:> > Hi All, > > I would like to know if this is possible and if possible what is the > complexity. > > Consider a CIFS client, SAMBA Server1 and Samba Server2. > > Say a session is established between a CIFS client and SAMBA server1. Is it > possible for the SAMBA server1 to transfer/redirect/reestablish the > connection to SAMBA server2 without the CIFS client knowing about this? The > session between the CIFS client and SAMBA Server1 should be closed and a > session between CIFS client and SAMBA server2 should be opened both > transparent to the CIFS client.Look into MSDFS, which sends back a special error code to indicate 'this directory not on this server', the client then asks for the real server and tranparently reconnects. Andrew Bartlett -- Andrew Bartlett abartlet@pcug.org.au Manager, Authentication Subsystems, Samba Team abartlet@samba.org Student Network Administrator, Hawker College abartlet@hawkerc.net http://samba.org http://build.samba.org http://hawkerc.net
Hi, Thanks for your response. Andrew, The MSDFS works on the DIRECTORY level. i.e. even before it establishes the CIFS session, it identifies the correct CIFS server. If the server1 finds that the directory is not there, it returns an error and the client finds out where the directory is located from server1. My problem is the directory is located in CIFS server1 and the client connects to it. But the file the client is going to open from that directory is moved to another server CIFS Server 2 for some reason. Also the CIFS server1 fakes the clients that the file is still in CIFS server1. How to resolve this? In essence I want "LOCATION TRANSPARENCY and LOCATION INDEPENDENCE" at FILE level and I want the redirection to work at FILE level. Barry, I do not want the CIFS Server1 to get the data from CIFS Server2 and server the client. In this case there will be a big performance hit for large files because of the two hops from Server2 to Server1 and from Server1 to client. Also the file is moved to Server2 from Server1 to make the access faster. If we are going to have two hops the whole purpose of moving file from server1 to server 2 is defeated. -Siva -----Original Message----- From: Barry Johnson [mailto:originalskinnyj@hotmail.com] Sent: Thursday, February 21, 2002 6:37 AM To: Andrew Bartlett; Sivaselvam, CN Cc: samba@lists.samba.org Subject: Re: [Samba] CIFS Session transfer If you don't want to use DFS you could use NFS. Samba server2 exports it, Samba server1 mounts it, samba shares it, voila transparent to the end user Barry Johnson ----- Original Message ----- From: "Andrew Bartlett" <abartlet@pcug.org.au> To: "Sivaselvam, CN" <cn.sivaselvam@digital.com> Cc: <samba@lists.samba.org> Sent: Wednesday, February 20, 2002 6:37 PM Subject: Re: [Samba] CIFS Session transfer> "Sivaselvam, CN" wrote: > > > > Hi All, > > > > I would like to know if this is possible and if possible what is the > > complexity. > > > > Consider a CIFS client, SAMBA Server1 and Samba Server2. > > > > Say a session is established between a CIFS client and SAMBA server1. Isit> > possible for the SAMBA server1 to transfer/redirect/reestablish the > > connection to SAMBA server2 without the CIFS client knowing about this?The> > session between the CIFS client and SAMBA Server1 should be closed and a > > session between CIFS client and SAMBA server2 should be opened both > > transparent to the CIFS client. > > Look into MSDFS, which sends back a special error code to indicate 'this > directory not on this server', the client then asks for the real server > and tranparently reconnects. > > Andrew Bartlett > > -- > Andrew Bartlett abartlet@pcug.org.au > Manager, Authentication Subsystems, Samba Team abartlet@samba.org > Student Network Administrator, Hawker College abartlet@hawkerc.net > http://samba.org http://build.samba.org http://hawkerc.net > > -- > To unsubscribe from this list go to the following URL and read the > instructions: http://lists.samba.org/mailman/listinfo/samba >
"Sivaselvam, CN" wrote:> > Hi, > > Thanks for your response. > > Andrew,> In essence I want "LOCATION TRANSPARENCY and LOCATION INDEPENDENCE" at FILE > level and I want the redirection to work at FILE level.This does not exist in CIFS. I suggest you see if you can find another protocol more suited to your task. Andrew Bartlett -- Andrew Bartlett abartlet@pcug.org.au Manager, Authentication Subsystems, Samba Team abartlet@samba.org Student Network Administrator, Hawker College abartlet@hawkerc.net http://samba.org http://build.samba.org http://hawkerc.net
Andrew, I understand this does not exist in CIFS. My earlier question regarding transferring the already established CIFS session between a client and server1 to client and server2 transparent to the client is in this regard. I would like to know if this is possible and what are the caveats in attempting this? -Siva -----Original Message----- From: Andrew Bartlett [mailto:abartlet@pcug.org.au] Sent: Thursday, February 21, 2002 12:28 PM To: Sivaselvam, CN Cc: 'Barry Johnson'; Andrew Bartlett; samba@lists.samba.org Subject: Re: [Samba] CIFS Session transfer "Sivaselvam, CN" wrote:> > Hi, > > Thanks for your response. > > Andrew,> In essence I want "LOCATION TRANSPARENCY and LOCATION INDEPENDENCE" atFILE> level and I want the redirection to work at FILE level.This does not exist in CIFS. I suggest you see if you can find another protocol more suited to your task. Andrew Bartlett -- Andrew Bartlett abartlet@pcug.org.au Manager, Authentication Subsystems, Samba Team abartlet@samba.org Student Network Administrator, Hawker College abartlet@hawkerc.net http://samba.org http://build.samba.org http://hawkerc.net
Hi Andrew, Thanks for your inputs. I agree that we need a server preying for other servers. The catch here is there should not be any need to change the CIFS client. The solution should work with any CIFS client without having to change the CIFS client or without having to add some service over CIFS client. I will only have the liberty to change the CIFS server implementation to provide this solution. All the CIFS servers participating in this solution can be aware of this extensions to the CIFS behavior. -Siva -----Original Message----- From: Andrew Bartlett [mailto:abartlet@pcug.org.au] Sent: Thursday, February 21, 2002 2:01 PM To: Sivaselvam, CN Cc: samba@lists.samba.org; 'Andrew Bartlett'; 'Barry Johnson' Subject: Re: [Samba] CIFS Session transfer "Sivaselvam, CN" wrote:> > Andrew, > > I understand this does not exist in CIFS. > > My earlier question regarding transferring the already established CIFS > session between a client and server1 to client and server2 transparent to > the client is in this regard. > > I would like to know if this is possible and what are the caveats in > attempting this?This is not possible, excecpt by MSDFS. In theory, it might be possible for one host to hijack a connection to another, but it would need to have full vuid/tid/fd tables before it would even start to look like it worked. The closest I can come is the suggestion (mad earlier) that you could have one server 'proxy' for another, or a 'frontend' server proxying for a number of backends. (I understand some cluster arrangements do this). Andrew Bartlett -- Andrew Bartlett abartlet@pcug.org.au Manager, Authentication Subsystems, Samba Team abartlet@samba.org Student Network Administrator, Hawker College abartlet@hawkerc.net http://samba.org http://build.samba.org http://hawkerc.net