LVM-Howto [Was : what are the restrictions on bootablepartitions?]
Ow Mun Heng
ow.mun.heng at wdc.com
Fri Apr 30 09:17:33 UTC 2004
> -----Original Message-----
> From: neil [mailto:neilcuk at aol.com]
>
>
> mr700 at globalnet.bg wrote:
>
> >On Friday 30 April 2004 05:11, Ow Mun Heng wrote:
> >
> >
> >>>-----Original Message-----
> >>>From: neil [mailto:neilcuk at aol.com]
> >>>Sent: Thursday, April 29, 2004 10:35 PM
> >>>To: For users of Fedora Core releases
> >>>Subject: Re: what are the restrictions on bootable partitions?
> >>>
> >>>
> >>>
> >>>
> >>>rpjday at mindspring.com wrote:
> >>>
> >>>
> >>>
> >>>> what are the restrictions on where i can install another
> >>>>
> >>>>
> >>>linux distro
> >>>
> >>>
> >>>>onto my fedora core (actually, FC2-t3) system so that grub
> >>>>
> >>>>
> >>>can find it?
> >>>
> >>>
> >>>>(even though this is a test version of fedora, this
> question actually
> >>>>refers to FC distros in general.)
> >>>>
> >>>>
> >>>>
> >>>>
> >>>There are no restrictions other than the boot loader (grub)
> >>>must be able
> >>>to read the boot partition.
> >>>
> >>>
> >>>
> >>>> typically, for historical reasons, even when i use LVM, i
> >>>>
> >>>>
> >>>create a small
> >>>
> >>>
> >>>>primary, ext3 filesystem for /boot, and use LVM for the rest
> >>>>
> >>>>
> >>>of the drive.
> >>>
> >>>
> >>>>is there any compelling reason for doing this anymore?
> what's the
> >>>>recommended strategy for LVM? and need for a non-LVM
> >>>>
> >>>>
> >>>filesystem on newer
> >>>
> >>>
> >>>>machines?
> >>>>
> >>>>
> >>>>
> >>>It really depends on what the system will be used for.
> Check out the
> >>>howto here: http://www.tldp.org/HOWTO/LVM-HOWTO/index.html
> >>>
> >>>
> >>I've actually looked through the howto but am still unable
> to determine
> >>how to actually create a lvm system. I've recompiled my kernel to
> >>have the devive mapper as a module and modprobe'ed it.
> >>
> >>When I try to do vgscan it states that the kernel modules
> are not loaded.
> >>
> >>
> > I don't remember how I did this with RH9 to make it
> work, but I remember
> >I played a bit whth modprobe, the LVM tools and the man pages :)
> >
> >
> >>Please help.
> >>
> >>
> >http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/s
> ysadmin-guide/ch-lvm.html
> >http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/s
> ysadmin-guide/ch-lvm-intro.html
> >http://www.redhat.com/docs/manuals/linux/RHL-8.0-Manual/custo
> m-guide/ch-lvm.html
> >http://www.redhat.com/docs/manuals/linux/RHL-8.0-Manual/custo
> m-guide/ch-lvm-intro.html
> >http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/custom-
> guide/ch-lvm-intro.html
> >...
> > I did install FC1 with Software Raid 5 and LVM on top of
> it, but doing so on less
> >than three physical disks results to up to 5 times slower
> transfer (because of the
> >raid). If you have 3 disks read speed increases and the
> write speed is almost the
> >same. Using ReiserFS I was able to resize 61G LV to 64G LV
> without errors. With
> >ext3 it worked, but fsck.ext3 had a lot of work to do (the
> partition was ~50G full).
> >I hope one day online resize will work with bouth and
> reiserfs will get more stable
> >with acl and SELinux support.
> > http://www.aplawrence.com/Linux/lvm.html
> > ps: putting the /boot partiton ouside the LVM worked fine for me.
> >
> >
> >
> okay - there are a few steps one needs to take to get their
> system using
> LVM. It can be tricky to get your brain around at first but
> it will slot
> into place. The steps are quite straight forward - even when
> setting up
> post install. Here's a brief overview. I'm assuming you can
> follow the
> man pages of each of the commands specified - there are a number of
> options which will be up to you:
>
> as root
> One(a): Make sure you have backed up any important data
> before trashing
> your system ;-)
> One: make sure your kernel supports LVM (By default this is
> supported in
> FC1)
> Two: create some LVM partitions (of type 8e under fdisk)
> Three: reboot or execute partprobe
> Four: execute vgscan
> Five: use pvcreate to assign your newly typed disks as use
> within the LVM
> (actually, four and five might be back to front)
> Six: use vgcreate to generate a new volume group (and add
> some physical
> volumes tro it)
> Seven: use lvcreate to make your logical volume
> Eight: format your new logical volume
>
> then it's up to you - mount as you like
>
> use e2fsadm to extend and reduce the size of the volume
>
> There is a huge amount of documentation and you should really get to
> grips with resizing, adding new PVs etc. Before you start
> putting useful
> data on your new LV!
Thanks for the info Neil. I think I do have a hang of it.. sort of anyway.
So, what you're saying is that I have to create the LVM partition using
fdisk
1st before I can get to execute vgscan??
Currently I just type vgscan and then it complains
vgscan -- LVM driver/module not loaded??
(it's loaded. The module is named dm-mod.ko right??)
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