Re: Installer: problem installing onto LVM on RAID1
On 04/09/2017 08:43 PM, Ron Leach wrote:
> List, good evening,
>
> I am trying to install Debian onto an LVM, and I want the LVM to use a
> pair of disks in a RAID1 configuration. I'm having difficulty
> instructing the partitioner to do this.
>
> I have a new, empty, machine with 2 x 3TB disks. This new machine is
> intended to replace our existing users-files server, which has nearly
> exhausted its current fit of RAID1 on 2 x 2TB disks. (The server of the
> files uses samba and NFS.) Some time ago I received advice from the
> raid list that in future I could consider using an LVM so that when an
> existing volume is full it (if it is an LV) can be extended across
> additional disks. Now that our existing system has reached its capacity
> limit, I'd like to replace it - and also take that advice.
>
> While trying to install Debian 7.11/amd64 onto the new HW, I reach the
> partitioner and can (first) set up a single md (md0) RAID1 over the 2 x
> 3TB disks. Next I can set up an LVM physical volume (3TB), and I can
> then set up a 3TB logical volume for '/'. (I think I'm happy with the
> system, /home, and the general 'users-files' filesystem all sharing the
> one logical volume - similar to how a simple basic Debian install can be
> done on a whole disk.)
>
> But the installer complains because I don't have any swap - and (in
> addition) I am unsure if I need to do something different for GRUB and
> booting. I first tried using the 'guided' partitioner (I thought it
> might 'know best' about needing boot and / and so on) but I didn't seem
> to be able to ask it to use RAID *and* LVM. I could ask it to make a
> RAID1, or an LVM. May I ask the list a couple of questions?
Hi Ron.
> What partitions - I think I mean logical volumes - might I be best using
> for my installation, keeping in mind that I will need to extend whatever
> logical volume houses the 'users-files'?
Yes, it will be better LVM to be used in your case.
The hierarchy in LVM is:
- physical volume - this can be a disk, RAID array or partition
- volume group - this contains one or more physical volumes. In the
future you can add new physical volumes to volume group.
- logical volume - this contains file system and files and belongs to
particular volume group.
> Is using a whole-disk RAID1 a reasonable choice (the kernel raid wiki
> suggests this will work) or would folks on the list recommend
> configuring multiple mds?
I don't know any downside of using one MD device.
If I was you I would do the following:
- use GPT partition table for both disks
- create one partition on each drive for Grub second stage image and
make it big enough. For EFI systems I read that the partition should be
about ~256MB, but if they are bigger that won't hurt, mine are 1GB.
- create RAID partition on each disk and build one big RAID 1 array (a
MD device)
- on top of this RAID 1 array create a physical volume
- create a volume group and add the physical volume to it
- create logical volumes for the system like you usually do. For
example some people create different file systems for:
/,
/home,
/usr,
/var, etc.
- create a logical volume for your file server content
- install the OS.
By the way I have not used LVM on Debian, but I believe that Linux LVM
HOWTO can be your friend.
HTH
Kind regards
Georgi
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