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Re: Procedure? Move existing Wheezy from sda2 to md1



 Hi.

On Sun, 19 Jan 2014 16:15:31 +0000
Ron Leach <ronleach@tesco.net> wrote:

> 1. First insert the 2 3TB drives and, using the existing Wheezy, 
> create a raid1 array.  I would create three md arrays:
> md0 for Grub, 100 MB
> md1 for Wheezy, 250 GB
> md2 for the LV filesystem, approx 2.75 TB.

Given you're using >2Tb disks, GPT would be nessessary, and GRUB2 will
fail to install unless you'll create special 'bios_grub' partition.

I did similar thing recently, and my setup was:

bios_grub partition for grub2 (it failed to boot without it) - 1Mb
md0 for grub - 128Mb
md1 as a physical volume for the rest of the RAID1.

I've put root filesystem, /var filesystem and swap on a volume group on
a LVM to simplify backup. GRUB was installed on both disks. bios_grub
was put on both disks.


> 3. The Debian installer created several partitions for the Wheezy 
> install and, in my plan, I do not have those partitions replicated in 
> the raid1 system.  So, moving (or copying, perhaps, is a better word) 
> Wheezy to /dev/md1 poses a little more difficulty.  Though I would 
> have used DD if it were simply a matter of copying from one whole disk 
> to another, this time I need to copy the whole of '/' (which is 
> mounted on several partitions), while retaining all the metadata, etc. 

Don't use dd for this unless you remount filesystems read-only (or
unmount them). I used this:

https://wiki.debian.org/ReadonlyRoot

so things were simple for me (i.e. create lv, copy block device into
lv).


>   I think I would need to
> (a) create a filesystem on md1, and then
> (b) use cp, perhaps, as root, to copy the whole of / (excluding any 
> nfs mount points).  I've previously used the '-a' option with cp to 
> ensure that metadata is retained.

Will work, although I'd prefer tar or cpio for this.


> But I worry this won't work because /usr (for example) is a separate 
> mount point in fstab and I'll have to remove those (because the whole 
> of / would now be on a single partition), but I'm not sure if fstab 
> would be the only thing that needed to change.

At very least, you'll also need to reinstall GRUB on the RAID1 and
rebuild initrd. Whenever you'll keep /usr separate, or not is
irrelevant.

Reco.


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