LVM-Howto [Was : what are the restrictions onbootablepartitions?]
Ow Mun Heng
ow.mun.heng at wdc.com
Fri Apr 30 09:36:13 UTC 2004
> -----Original Message-----
> From: neil [mailto:neilcuk at aol.com]
> Sent: Friday, April 30, 2004 5:26 PM
> To: For users of Fedora Core releases
> Subject: Re: LVM-Howto [Was : what are the restrictions
> onbootablepartitions?]
>
>
>
>
> ow.mun.heng at wdc.com wrote:
>
> >
> >
> >>-----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??)
> >
> >
> >
> >
> >
> >
> you've got me there. It should be 'lvm-mod' that gets loaded. try a
> manual 'modprobe lvm-mod'. If that works try running 'depmod'
> to setup
> the module dependancies again. Sounds like something is missing the
> mark. Create one or two partitions using fdisk and try vgscan again.
did I mention i was using 2.6 kernel??
The 2.6 kernel compiled it as dm-mod
Oh well.. I'll try again..
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