On lun, 2005-10-31 at 11:20 -0700, Dale.R.Fowle@xxxxxxxxxxx wrote: > Hi all, I'm wondering if anyone can help un-confuse me. =-) > > I've been through about every document I can find on the internet trying to > chase down exactly how I'm supposed to configure devices for MPIO. I > haven't seen the same answer twice. Everything is different. > > The most formal documentation I found was here: > http://portal.suse.com/sdb/en/2005/04/sles_multipathing.html > > I've also been out to the multipath-tools resource page: > http://christophe.varoqui.free.fr/ > I bet you'll volonteer to make some really nice doc when you'll have a good insight of Linux mp-tools. :/ > I really haven't gotten anything to work yet. =-) > > I also saw another issue addressed from this e-mail discussion board that > said really all you need to do is uncomment some lines in > /etc/multipath.conf and comment out some other lines and you're good to go. > Yes, it all boils down to that. But for a safe start, you should be happy with no config file at all. Safe defaults should apply, and you can tweak one param at a time from there to see its effect. > So, to clear things up with the device mapper piece of things. Is there any > requirement of the multipath command that these devices have to be > pre-built using dmsetup before multipath will recognize and built a path > under /dev/dm-*? No. dmsetup is not recquired for mpio operation. As for /dev/dm-* : they are not recquired to exist at all. The agreement is to use /dev/mapper/{alias,wwid} nodes. > If so,...how do you setup two paths to one device in your > target_file? No target_file. No manual assemble. > What's confusing to me for setting up two devices in a > "linear" fashion would seem like it's creating a concatenation of two > separate devices instead of creating two paths to one device (i.e. "0 > 1028160 linear /dev/hda 0 1028160 3903762 linear /dev/hdb 0" from the > dmsetup manpage). The only other options are to set them up as stripe or > error devices. > linear, stripe, error, multipath, ... are target policies. Concatenation is the *only* policy to chain multi-line tables. Each line can have a different target policy. multipath-tools use only 1-line tables. All paths of a multipath are specified on this single line. Users should not have to mess with this low-level stuff. > I'm not sure where to go next with this. I can see my two paths at /dev/sda > and /dev/sdb. Whether I partition them or not, multipath won't pick > anything up and display it with 'multipath -v2 -d' or 'multipath -l'. What > I get from 'multipath -v2 -d' is an error like this: > > #multipath -v2 -d > error calling out /bin/false > error calling out /bin/false > # > multipath -d won't do anything (dry mode). You need to comment out the /bin/false prioritizer in the config file. > Also, does multipathd or the multipath command itself update > /etc/multipath.conf when multipath configures or recognizes a device,..or > is it all a manual process? The tools never touch /etc/multipath.conf > I can't say I've ever seen a device addressed > like this before: > > 3600601607cf30e00184589a37a31d911 > > > Coming from a Solaris background, I'm used seeing the WWNN and/or the WWPN. > =-) I'm pretty new to the Linux world, so I understand that I'll have to > get used to seeing things differently sometimes. > This is the default naming before recent upstream version. You'll find the nodes in /dev/mapper/ > Anyways, I'd appreciate any help anyone can offer. FYI, I'm running SLES 9 > with SP2, multipath-tools 0.4.4 is installed, and I'm using a pair of > Qlogic 2340 HBAs. The storage array controllers are configured as > active/active. The Qlogic failover parameter is disabled due to my previous > trials playing with mdadm's mpio features as well. > Good. Keep it that way. Regards, cvaroqui -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
