Lee, By your initial description, it looks like you are not seeking to do multipathing but to configure a shared library environment. If you have a tape library with multiple drives and two TSM servers and you want both TSM servers to be able to access all of the drives, you should designate one of the TSM servers to be a library manager and the second TSM server to be a library client.
For example; - you have one library with 8 drives and two TSM servers TSM1 & TSM2. - TSM1 will be the library manager and TSM2 will be the library client - TSM1 has four fiber channel ports. Each port is zoned to two of the tape drives (no multipathing is needed) - TSM2 also has four fiber channel ports and each port is zoned to two of the tape drives - at this point, each tape drive is attached to both servers and each server sees all 8 tape drives Now you have a problem because a tape drive can only be used by one server at a time. If you did nothing else, you would experience problems with tape drive access. But this problem is not really a problem because TSM has the "library manager" functionality where a single TSM server coordinates access to tape drives. When the library client needs a drive, It requests access to a drive from the library manager. The manager grants exclusive access to that drive to the library client. When the library client is finished using the drive, it notifies the library manager and the library manager removes that exclusive access. Everyone is happy. - Set up TSM1 as a library manager and TSM2 as a library client as detailed in the TSM server guide, In this way, you can efficiently allocate all of your tape resources to all of your TSM servers and they share the resources nicely. - Just ensure that your path definitions for both TSM servers are correct for that server. i.e. rmt1 on TSM1 may be rmt6 on TSM2. Multipathing from a server to a tape drive will create multiple instances of the same drive (i.e. rmt0 and rmt5 both point to the same physical drive) which can be used in a HA environment to ensure that if a physical path fails (i.e. rmt0), a second path (rmt5) to the device is available. In the above example scenario, there is no multipathing used. Cheers, Neil Strand From: "Lee, Gary" <[email protected]> To: [email protected], Date: 05/23/2014 02:52 PM Subject: Re: [ADSM-L] multipathing ts1120s under RHEL6 Sent by: "ADSM: Dist Stor Manager" <[email protected]> Ok, unloading multipath. How do I deal with the issue of multiple paths to each drive? I have four fc ports all connected to the san. Sorry to appear dense, just not familiar with fiberchanel. -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of Cameron Hanover Sent: Friday, May 23, 2014 2:24 PM To: [email protected] Subject: Re: [ADSM-L] multipathing ts1120s under RHEL6 To expand on it slightly, add this option for modprobe once lin_tape is isntalled: options lin_tape alternate_pathing=1 http://publib.boulder.ibm.com/infocenter/tsminfo/v6/index.jsp?topic=%2Fcom.ibm.itsm.srv.doc%2Fc_multipath_io_support_unix.html - Cameron Hanover [email protected] When any government, or church for that matter, undertakes to say to its subjects, this you may not read, this you must not see, this you are forbidden to know, the end result is tyranny and oppression, no matter how holy the motive. --Robert A. Heinlein On May 23, 2014, at 1:39 PM, Michael Prix <[email protected]> wrote: > Gary, > > dm-multipath is for diskdrives. You want to use lin_tape for the > handling of the FC-attachment of the tape drives. > > -- > Mit freundlichen Grüßen / Kind regards > > Michael Prix > > On 05/22/2014 09:14 PM, Lee, Gary wrote: >> I am now attempting to share libraries containing IBM ts1120 drives between two tsm servers on HP hardware running RHEL 6. >> >> It appears that I will need to use the dm-multipath system to manage the various fc paths to all the drives. >> >> Got dm-multipath installed, but now trying to configure so it will see the drives. >> Has anyone done this before and could you point me to some information? >> I have the redhat manual for configuring dm-multipath. I am fairly new to FC so some help is appreciated. >> The redhat book does not even mention tape, and can't find info on my drives in the places it mentions to look. >> >> Thanks for any and all help.
