Linux on 390 Port <[email protected]> wrote on 06/05/2007 01:45:52 PM:
> Here's what we were told: > > Without NPIV, the FCP CHPID acts like a shared HBA, and all LUNS are > visible to all virtual machines in all LPARs. Only one OS instance can > use a given LUN, however. If another tries, the LUN will appear busy. > > WITH NPIV, the system assigns an arbitrary virtual WWPN to each > individual address (device number/subchannel). On the storage side, the > SAN admins map/mask/whatever to the virtual HBA port names. The LUNs > can be mapped to multiples, so sharing LUNs is possible. > > To share tape drives between zLinux instances for TSM server, NPIV is > required. > > For us, this whole business of arbitrary virtual port names has serious > DR implications. That, coupled with the whole business of having to > code specific WWPNs in zfcp.conf, has caused us to proceed very slowly > with FCP devices in general. > NPIV WWPNs only change when you make changes to your IOCDS. You can rely on a particular subchannel to always get the same WWPN. Otherwise, it would be an administrative nightmare! Have a look Volker's Share presentation on slides 11, 12: http://linuxvm.org/present/SHARE107/S9257vs.pdf Thanks, Ray Higgs System z FCP Development Bld. 706, B24 2455 South Road Poughkeepsie, NY 12601 (845) 435-8666, T/L 295-8666 [EMAIL PROTECTED] ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
