Hi Michael, Fri, 25 Oct 2013 11:39:32 +0400 Michael Tokarev <mjt@xxxxxxxxxx> ==> linux-raid <linux-raid@xxxxxxxxxxxxxxx> : > Hello. > > Is there a way to change some parameters - like preferred minor, > array name, homehost, guuid and the like - of a _running_ array? > I understand these can be changed using --assemble --update=foo, > but how about, say, root array which is being assembled from > within an initrd with limited functionality? > > What I'm trying to achieve is to make a clone of a (remote) > running system, in order to upgrade hdds. For this, a new > set of drives are inserted, new set of filesystems is created, > current filesystems are copied to new hdds and on the next > reboot the system should boot from the new hdds. But since > I can't create arrays with the same names/minors as currently > running ones, and I want to preserve the naming scheme, I > need to ensure the new arrays will be named correctly after > the reboot. But since the system is remote, this is a bit > difficult to achieve for the root device. > > And similarly, I can't --update a NON-running array without > --assemble, so I can't fix the names before reboot while the > old arrays are still running. > > Maybe the easiest way is to write a small (perl) program > which will read the superblock of a non-running array, update > it and write it back. This at least will allow me to perform > tasks before reboot. But this way it becomes risky - if the > first reboot will happen with the old drives still in place, > havoc might happen, since more than one array will have the > same name... > > So a better route will be to create new arrays with temp > names, reboot, change names on the newly running system, > and remove old arrays. The question is how to change > some params on a running system. > it depends on the distribution you're running. But you might not need to change these parameters while the system is running. I can update /etc/mdadm/mdadm.conf with the UUIDs of the new arrays and regenerate the initrd with # update-initramfs -u running ubuntu. And then after the reboot the arrays are named like I told before in the mdadm.conf. Good luck Lars > Thanks, > > /mjt > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
