[dundee] a few questions re LVM, filesystems and VBox

[gordon dunlop]

On 23 September 2010 09:02, garryg <gargul1969 at gmail.com> wrote:

> Morning folks,
>
> I have a few questions for y'all and hope someone/anyone can help
> clear things up for me. I'll try to be as brief as poss.
>
> 1) I've installed Ubuntu 9.10 using the alternate install cd so i
> could encrypt my hard drive and then partition using the LVM - that's
> all fine. After install, i can create new logical volumes ok but when
> mounted i only have ro permissions as group owner is root (still don't
> quite get that one when the LVs were created using my root pwd -
> another time for that one). Anyway, once the new LVs are mounted i can
> (re)format each LV using Ubuntu's Palimpsest Disk Utility and take
> ownership of the filesystem that way, getting me both read and write
> permissions. It just seems a pretty round about way of getting there
> and I'm pretty sure after a scan of lvm2 documentation that doing this
> would probably be a lot simpler from the command line, but i ain't
> there yet... So, basically, am i ok using this method to create new
> LVs or am i storing up future trouble for myself here by mixing lvm
> and disk utility to achieve my ends?
>
> I will  handle 1 & 3 together. Best thing for me to do is give you an
example overview.

 LVM, mount points & fstab:

 On installing your distro create your logical volumes with mount points, a
bit like physical partitions with the added facility of having your own
naming nomenclature for further logical volumes. eg

lvol1    /
lvol2   /home
lovl3   /var
lovl4  /vm

Entries would be automatically written in the /etc/fstab file for mounting
these logical volumes at boot. If a new logical volume was then created with
mount point  /backup then an entry will have to be made in the fstab file
for this logical volume to be mounted at boot time. If you wanted it mounted
after fstab entry without re-booting do a  "mount -a command". If you do not
want a logical volume to mount at boot time just do manual mounting like
what you are doing now.

Permissions:

After the creation of the logical volumes as defined above, all volumes and
directories, with the exception of the directory garry in the /home volume,
will be designated as having root permissions which is standard Linux policy
and and maintains the security of the system. Permissions and read/write
modes can be changed using super user status in the command line i.e. sudo
for Ubuntu and using the chown,chgrp & chmod commands.

So the easiest thing to do is to create a directory e.g. machines (for
storing your virtual images)in lvol4 (/vm) using sudo on the command line
and then change the user and group to garry with read/write permissions.

I hope this explains things.

2) I wanna do a fresh install to get things ready for starting my OU
> course next month and wanna make a bunch of LVs for VMs as trying
> out/working with different distros is part of the course work i
> believe. However, the newest version of vbox (3.2.8 - not the ose)
> tells me it doesn't like being used on an ext4 fs. So, should i make
> them ext2 or ext3 or does it not really matter? Oh, thanks for the nod
> Gordon re using the most up-to-date version as i can get USB support
> no prob now which makes a big difference - i may even finally be able
> to get that damn dongle working through a hawk, spit, windows distro
> in a VM (i've tried and tried but just can't get it to work with
> Ubuntu unfortunately - i know it can be done but it's beyond me the
> now).
>
>   There has been some problems with this new Virtualbox version and host
ext4 systems, have a look here:

http://forum.virtualbox.org/viewtopic.php?f=1&p=150220

I have had no problem with guest ext4 systems with this version.

Gordon


> 3) mount points: when creating a new partition(s) - LV or otherwise -
> should i be assigning mount points or is it ok to just mount when
> required as if they're external media? That's what i've been doing so
> far (they just get mounted at /media and all seems to work fine for me
> this way. Again though, i wonder if i'm storing up trouble going about
> things in this fashion?
>
> Ok, i'll leave it at that for now. Any and all input will be very much
> appreciated indeed. Thanks.
>
> Cheers,
>
> Garry.
>
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