On Saturday 13 November 2021 07:33:49 Andy Smith wrote: > Hello, > > On Fri, Nov 12, 2021 at 11:42:32AM -0500, Gene Heskett wrote: > > On Friday 12 November 2021 10:18:07 Dan Ritter wrote: > > > After you have set them up, mdadm.conf has things like this: > > > > > > ARRAY /dev/md/0 metadata=1.2 name=debian:0 > > > UUID=aeac6271:676b1852:04f077d6:fcd285d6 ARRAY /dev/md/1 > > > metadata=1.2 name=debian:1 > > > UUID=d74ff881:2e966c37:ec6ef1ec:75b8cdce ARRAY /dev/md/2 > > > metadata=1.2 name=debian:2 > > > UUID=7c56166b:0d5aed8b:a9d03c45:e9b8080c > > > > That doesn't appear to be true. I have run the create which seemed > > to be ok, then mkfs -text4 /dev/md0, then mounted it at /home2. > > > > But /etc/mdadm/mdadm.conf doesn't yet have any of that, only this: > > You don't need to list the arrays in /etc/mdadm/mdadm.conf since > udev assembles arrays based on the metadata that exists on each > device. It's fine for there to be no ARRAY lines in there. These > days it's only really useful in recovery situations or for setting > some special options per array. > > You can still do the > > # mdadm --detail --scan > > to find the lines to put in the mdadm.conf yourself. > > > And again, I don't trust UUID's as moving a drive cable to a > > different socket has invalidated the whole lot of them once before. > > I would much rather LABEL the array, and mount it in /etc/fstab by > > that label. > > There may be some conceptual error here. The UUIDs you would put in > /etc/fstab are FILESYSTEM UUIDs, not array UUIDs. Lots of things in > computing have UUIDs. > > After you put a filesystem on each array you can refer to the > FILESYSTEM label in /etc/fstab. These labels are internal to each > filesystem and nothing to do with any layer below, such as md. > > > LABEL as I recall is a journalctl function? Does it work on > > raid10's? > > Filesystem labels have nothing to do with journalctl. And I don't > know what you mean by them being "a function". > > Again, filesystems (can) have labels, these are a filesystem detail, > RAID doesn't know nor care. > > > Humm, now: > > gene@coyote:~/AppImages$ sudo mdadm --detail --scan > > [sudo] password for gene: > > ARRAY /dev/md0 metadata=1.2 name=coyote:0 > > UUID=8ad67ef1:a14d63ab:c684ec2b:42a0c011 > > > > So I should add that last line to which category in mdadm.conf? > > mdamd.conf doesn't have categories. You would just append that line > at the end, ensuring it is all on one line.
And I just found I didn't have an mdadm.conf, and I had figure a new -C would have created it. But the last time I ran it, no mdadm.conf was created. So I made a 2 liner from the --scan output. What else should it have? ARRAY /dev/md0 metadata=1.2 name=coyote:0 UUID=3d5a3621:c0e32c8a:e3f7ebb3:318edbfb ARRAY /dev/md1 metadata=1.2 name=coyote:1 UUID=ddb6ffa2:e068b701:f316cc5f:83938a13 You indicate that these are not the UUID's to put in fstab, or do I miss-understand? Experiment after putting those UUID's into fstab @coyote:etc$ mount /home2 mount: can't find UUID=3d5a3621:c0e32c8a:e3f7ebb3:318edbfb root@coyote:etc$ mount /snapshot mount: can't find UUID=ddb6ffa2:e068b701:f316cc5f:83938a13 root@coyote:etc$ mount /dev/md0 -text4 /home2 root@coyote:etc$ mount /dev/md1 -text4 /snapshot @coyote:etc$ df Filesystem 1K-blocks Used Available Use% Mounted on udev 16380992 0 16380992 0% /dev tmpfs 3280240 9516 3270724 1% /run /dev/sda5 1857400436 317616932 1445362976 19% / tmpfs 16401180 0 16401180 0% /dev/shm tmpfs 5120 4 5116 1% /run/lock tmpfs 16401180 0 16401180 0% /sys/fs/cgroup /dev/sdb1 229699916 61472 217900640 1% /sdb /dev/sdc1 1921802432 879249728 944860648 49% /amandatapes /dev/sda3 47799020 6444388 38896828 15% /var /dev/sda1 944120 188864 690080 22% /boot tmpfs 3280236 4 3280232 1% /run/user/1000 /dev/md0 1812963068 77852 1720721940 1% /home2 /dev/md1 100203600 61464 95009032 1% /snapshot Which nicely demos why I don't trust UUID's. But, why didn't it work? Why did I have to revert to md0/md1 names to remount them? > > And for the time being use that UUID in /etc/fstab to mount it to > > /home2, right? > > No, because that is not a filesystem UUID. And you said you wanted > to mount the filesystem by label anyway. So put whatever label you > chose when you did mkfs (or when you did it from the installer). I didn't know mkfs can do labels. > In a later email you did this: > > # mkfs -Text4 … > > and got an obscure error. > > That's because you did "-T" instead of "-t", which means something > completely different. You may want to get into the habit of doing: > > # mkfs.ext4 … > > instead as it's clearer and easier to remember. > > Cheers, > Andy Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
