Hello devs, I'm hoping that I can find the right person to help me on this list, as it seems this list is, by far, the greatest collection of people with expertise regarding dm-multipath. My desire: To locate a person who can write a hardware handler for the DS400 that will allow proper active/passive fail-over/fail-back, which we would be happy to sponsor financially (for contribution back to the project, of course). My situation: Our company has an existing IBM DS400 SAN that we are trying to deploy as part of a Oracle RAC project. In doing testing and analysis of the device and proper configuration of it for this purpose, I have learned that in a two controller configuration, this device is active/passive, and that in dm-multipath this results in the following configuration profile (from "multipath -ll" with all controllers connected): --------------------------------------------- ora_admin (20000d126733eaf14) [size=10 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:3 sde 8:64 [active][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:3 sdk 8:160 [active][ready] 20000d126733eaf17 [size=10 MB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:0 sdb 8:16 [active][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:0 sdh 8:112 [active][ready] ora_data1 (20000d126733eaf10) [size=200 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:5 sdg 8:96 [active][faulty] \_ round-robin 0 [prio=1][enabled] \_ 1:0:1:5 sdm 8:192 [active][ready] ora_archive (20000d126733eaf15) [size=50 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:4 sdf 8:80 [active][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:4 sdl 8:176 [active][ready] ora_redo2 (20000d126733eaf0b) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [prio=1][active] \_ 1:0:0:2 sdd 8:48 [active][ready] \_ round-robin 0 [enabled] \_ 1:0:1:2 sdj 8:144 [active][faulty] ora_redo1 (20000d126733eaf0a) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [prio=1][active] \_ 1:0:0:1 sdc 8:32 [active][ready] \_ round-robin 0 [enabled] \_ 1:0:1:1 sdi 8:128 [active][faulty] --------------------------------------------- And when controller 1 is unplugged, the configuration does the following: ora_admin (20000d126733eaf14) [size=10 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:3 sde 8:64 [active][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:3 sdk 8:160 [active][ready] 20000d126733eaf17 [size=10 MB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:0 sdb 8:16 [active][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:0 sdh 8:112 [active][ready] ora_data1 (20000d126733eaf10) [size=200 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:5 sdg 8:96 [failed][faulty] \_ round-robin 0 [prio=1][enabled] \_ 1:0:1:5 sdm 8:192 [active][ready] ora_archive (20000d126733eaf15) [size=50 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:4 sdf 8:80 [failed][faulty] \_ round-robin 0 [prio=1][active] \_ 1:0:1:4 sdl 8:176 [active][ready] ora_redo2 (20000d126733eaf0b) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [active] \_ 1:0:0:2 sdd 8:48 [failed][faulty] \_ round-robin 0 [enabled] \_ 1:0:1:2 sdj 8:144 [active][faulty] ora_redo1 (20000d126733eaf0a) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:1 sdc 8:32 [failed][faulty] \_ round-robin 0 [enabled] \_ 1:0:1:1 sdi 8:128 [failed][faulty] -------------------------------------------------- And when controller 2 is unplugged, the configuration does the following: ora_admin (20000d126733eaf14) [size=10 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:3 sde 8:64 [active][faulty] \_ round-robin 0 [active] \_ 1:0:1:3 sdk 8:160 [failed][faulty] 20000d126733eaf17 [size=10 MB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:0 sdb 8:16 [active][faulty] \_ round-robin 0 [active] \_ 1:0:1:0 sdh 8:112 [failed][faulty] ora_data1 (20000d126733eaf10) [size=200 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:5 sdg 8:96 [active][faulty] \_ round-robin 0 [enabled] \_ 1:0:1:5 sdm 8:192 [active][faulty] ora_archive (20000d126733eaf15) [size=50 GB][features="0"][hwhandler="0"] \_ round-robin 0 [enabled] \_ 1:0:0:4 sdf 8:80 [active][faulty] \_ round-robin 0 [active] \_ 1:0:1:4 sdl 8:176 [failed][faulty] ora_redo2 (20000d126733eaf0b) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [prio=1][active] \_ 1:0:0:2 sdd 8:48 [active][ready] \_ round-robin 0 [enabled] \_ 1:0:1:2 sdj 8:144 [active][faulty] ora_redo1 (20000d126733eaf0a) [size=68 GB][features="0"][hwhandler="0"] \_ round-robin 0 [prio=1][active] \_ 1:0:0:1 sdc 8:32 [active][ready] \_ round-robin 0 [enabled] \_ 1:0:1:1 sdi 8:128 [failed][faulty] -------------------------------------------------- I believe that without a proper hardware handler to instruct the DS400 to activate the passive controller and shift all LUNS in a timely fashion, that this storage unit will not be able to be used in a multipath manner for controller failover. Of course, it's quite possible that I am wrong, and there may be another way to make this active/passive configuration work without a hardware handler, and I'd be very happy to hear about any alternatives anyone may suggest. Would anyone here be willing to talk with me about our sponsorship of expanding the supported hardware list for dm-multipath to include this device? Does anyone know a person not already on this list who might be a good possibility as a developer for such a project? Thanks for you time in reviewing my post, and would appreciate any ideas, device, or direction any of you can provide. Sincerely, Kevin Taylor -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
