If anyone is using Linux multipathing... do you use mdadm multipathing, or DM-multipath multipathing? For extra points, why one over the other? Thanks. Andrew __________________________________________________________________ Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail. Click on Options in Mail and switch to New Mail today or register for free at http://mail.yahoo.ca _______________________________________________ StudioSysAdmins-Discuss mailing list StudioSysAdmins-Discuss@mailman.studiosysadmins.com http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss

Hi Andrew, As per my understanding "md" is to manage block devices for the purposes of LVM and Software RAID. And the "dm" subsystem is responsible for managing multipaths to the block level device. They have two completely seperate functions. I maybe wrong, but I was not aware that one could do multipathing using "md". Anand --- Anand S Bisen 818-723-9752 Sent from my iPhone. Please ignore the spelling mistakes. On Feb 8, 2010, at 2:45 PM, Andrew Klaassen wrote: > If anyone is using Linux multipathing... do you use mdadm > multipathing, or DM-multipath multipathing? > > For extra points, why one over the other? > > Thanks. > > Andrew > > > > > > __________________________________________________________________ > Be smarter than spam. See how smart SpamGuard is at giving junk > email the boot with the All-new Yahoo! Mail. Click on Options in > Mail and switch to New Mail today or register for free at http://mail.yahoo.ca > > _______________________________________________ > StudioSysAdmins-Discuss mailing list > StudioSysAdmins-Discuss@mailman.studiosysadmins.com > http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss _______________________________________________ StudioSysAdmins-Discuss mailing list StudioSysAdmins-Discuss@mailman.studiosysadmins.com http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss

dm-multipath -- it works very well for us going to all kinds of fiber- channel storage. If your storage cares about primary and secondary paths, you can usually find a mpath_prio_* script somewhere for your vendor, or if worst comes to worst, you can fudge it with a shell script. I agree with Anand -- I didn't know mdadm could do multipathing? I've always thought that the md subsystem was just for assembling different disks into a RAID-type device. -Sven On Feb 8, 2010, at 2:45 PM, Andrew Klaassen wrote: > If anyone is using Linux multipathing... do you use mdadm > multipathing, or DM-multipath multipathing? > > For extra points, why one over the other? > > Thanks. > > Andrew > > > > > > __________________________________________________________________ > Be smarter than spam. See how smart SpamGuard is at giving junk > email the boot with the All-new Yahoo! Mail. Click on Options in > Mail and switch to New Mail today or register for free at http://mail.yahoo.ca > > _______________________________________________ > StudioSysAdmins-Discuss mailing list > StudioSysAdmins-Discuss@mailman.studiosysadmins.com > http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss > _______________________________________________ StudioSysAdmins-Discuss mailing list StudioSysAdmins-Discuss@mailman.studiosysadmins.com http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss

Hi Anand, It surprised me, too, to learn that mdadm supports multipathing. But with a little more digging, I've learned that the maintainer of mdadm has deprecated it in favour of dm-multipath: http://lkml.indiana.edu/hypermail/linux/kernel/0903.0/01617.html I guess that answers my question. Andrew --- On Mon, 2/8/10, Anand Bisen wrote: > Hi Andrew, > > As per my understanding "md" is to manage block devices for > the purposes of LVM and Software RAID. And the "dm" > subsystem is responsible for managing multipaths to the > block level device. They have two completely seperate > functions. I maybe wrong, but I was not aware that one could > do multipathing using "md". > > Anand > > --- > Anand S Bisen > 818-723-9752 > > Sent from my iPhone. Please ignore the spelling mistakes. > > On Feb 8, 2010, at 2:45 PM, Andrew Klaassen > wrote: > > > If anyone is using Linux multipathing... do you use > mdadm multipathing, or DM-multipath multipathing? > > > > For extra points, why one over the other? > > > > Thanks. > > > > Andrew > > > > > > > > > >? ? ? > __________________________________________________________________ > > Be smarter than spam. See how smart SpamGuard is at > giving junk email the boot with the All-new Yahoo! > Mail.? Click on Options in Mail and switch to New Mail > today or register for free at http://mail.yahoo.ca > > > > _______________________________________________ > > StudioSysAdmins-Discuss mailing list > > StudioSysAdmins-Discuss@mailman.studiosysadmins.com > > http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss > _______________________________________________ > StudioSysAdmins-Discuss mailing list > StudioSysAdmins-Discuss@mailman.studiosysadmins.com > http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss > __________________________________________________________________ Looking for the perfect gift? Give the gift of Flickr! http://www.flickr.com/gift/ _______________________________________________ StudioSysAdmins-Discuss mailing list StudioSysAdmins-Discuss@mailman.studiosysadmins.com http://mailman.studiosysadmins.com/mailman/listinfo/studiosysadmins-discuss