3 ms·

What are the steps required today on Linux?

by jules 16y ago

viraptor 16y ago
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/first /dev/second Strangely, I think it was exactly the same 3 years ago. At least I don't remember doing anything complicated then. Although I did go via /etc/raidtab and mkraid. (I'm skipping over all the required apt-get / yum installs and creating the partitions with fdisk - this are of course standard simple dependencies) Edit: just noticed that there was a link to the previous post... where the guy did exactly this. The rest of the post is formatting the partitions, installing needed software, configuring grub, etc. I see his point, but I'm not sure I agree with it. Part of the original title "... To Run RAID-1 When You Didn't Plan For That Originally" sums it up. If you know how to handle partitions and how to configure your system in general, raid is just a one line difference. If someone gave me a windows box, I'd probably spend just as much time clicking around trying to figure out how to manage disks :)
- skorgu 16y ago
  He has the running / on /dev/first, he's migrating that to a degraded array of just /dev/second then bringing /dev/first in to complete the array.
skorgu 16y ago
The 3.5 year old steps are equally valid today for many and probably most cases. Been there done that and I'd never do it again; the cost of the hard drive isn't worth the blood pressure and strong drink this kind of juggling causes. IFF the machine was set up with LVM (and there's a single VG with the right properties) you could build the MD array degraded, add it as a PV under LVM and migrate the data at that layer[0] then nuke the old drive and add it to the array. I believe you could even do it without rebooting but I've never tried. Additionally, making distros boot from LVM isn't always straightforward, at minimum you'd probably have to get your hands dirty with grub. That said both BTRFS and zfs are (theoretically) "windows easy" for this case, once you're booting from them you can add mirrors to your heart's content and things should Just Work. [0] http://www.greyoak.com/lvmdrive.html http://www.greyoak.com/lvmdrive.html

What are the steps required today on Linux?

by jules 16y ago

What are the steps required today on Linux?

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/first /dev/second Strangely, I think it was exactly the same 3 years ago. At least I don't remember doing anything complicated then. Although I did go via /etc/raidtab and mkraid. (I'm skipping over all the required apt-get / yum installs and creating the partitions with fdisk - this are of course standard simple dependencies) Edit: just noticed that there was a link to the previous post... where the guy did exactly this. The rest of the post is formatting the partitions, installing needed software, configuring grub, etc. I see his point, but I'm not sure I agree with it. Part of the original title "... To Run RAID-1 When You Didn't Plan For That Originally" sums it up. If you know how to handle partitions and how to configure your system in general, raid is just a one line difference. If someone gave me a windows box, I'd probably spend just as much time clicking around trying to figure out how to manage disks :)

skorgu 16y ago
He has the running / on /dev/first, he's migrating that to a degraded array of just /dev/second then bringing /dev/first in to complete the array.

skorgu 16y ago

The 3.5 year old steps are equally valid today for many and probably most cases. Been there done that and I'd never do it again; the cost of the hard drive isn't worth the blood pressure and strong drink this kind of juggling causes. IFF the machine was set up with LVM (and there's a single VG with the right properties) you could build the MD array degraded, add it as a PV under LVM and migrate the data at that layer[0] then nuke the old drive and add it to the array. I believe you could even do it without rebooting but I've never tried. Additionally, making distros boot from LVM isn't always straightforward, at minimum you'd probably have to get your hands dirty with grub. That said both BTRFS and zfs are (theoretically) "windows easy" for this case, once you're booting from them you can add mirrors to your heart's content and things should Just Work. [0] http://www.greyoak.com/lvmdrive.html http://www.greyoak.com/lvmdrive.html