Kenny Lussier wrote: > > > This is true. For example, in /dev/mapper there is a device called > 350002ac00092072a1. I can label the device, but that also creates > labels on what the OS sees as /dev/sdc, /dev/sdd, /dev/sde, /dev/sdf, > /dev/sdg, /dev/sdh, /dev/sdi, and /dev/sdj, so a mount fails. The SAN > doesn't come with client-side multipathing software. That is really up > to the OS vendor. In this case, I am using device-mapper-multipath on > RHEL5.3AP (w/ their clustering suite) with a 3Par SAN. The SAN is > presenting all of the paths to both systems simultaneously. That isn't > a problem. And, if I wanted to use GFS to have the disk mounted to > both servers simultaneously, then that would work just fine. But, I > can't have the disk mounted on more then one system at any given time. > > I know the problem since I just did this across 4 systems for an Oracle install. We're using EMC gear, so I wound up using (and paying for) the EMC PowerPath software, which Does The Right Thing and presents disks as /dev/emcpower? and you can then have failover between FC connections. I even have some udev rules to set ownership correctly. The /dev/sd? disks still appear, but you don't want to use them directly for the reasons you mentioned.
I did a quick check on using device mapper, but I can't guarantee how disks appear from the SAN and DM appears to rely on using the /dev/sd? names to know where things go. Between that, the ease of use of PowerPath, the fact I wasn't paying for it, and I didn't have time to learn DM, I went with PowerPath. I think that's the clustering software that was referred to earlier. If you find a way to use DM in this manner, I'm interested to know your results and how you set this up. I'm also using RHEL 5.3. -Mark _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/