[linux-lvm] Total free space using added VGs and LVs

[Lou Arnold]

Brem,
I agree. I thought it should be possible. Perhaps someone else can try it
and let us know in a future blog. I just don't have enough experience to
take it farther.

Regards,
Lou.

On Sat, Oct 24, 2009 at 1:54 PM, brem belguebli <brem.belguebli at gmail.com>wrote:

> Hi Lou,
>
> Who is talking about unmounting root ?
>
> I'm just saying shrinking should be possible online as long as some
> conditions are met (FS usage less than X %, reduced fragmentation ...)
>
> Of course, this kind of procedure requiring a max of caution because
> of the high risk of data loss, I'm not sure it'll get implemented in
> the current tools.
>
>
>
> 2009/10/24, Lou Arnold <larnolda1 at gmail.com>:
> > Hahaha. Brem, you and I think alike. If you can do it let me know. I
> don't
> > think people can think of a way to keep the system on-line and yet
> dismount
> > root so that LVM commands can work on it. If you can make it work, I'll
> buy
> > you a virtual beer.
> > Regards,
> > Lou.
> >
> > On Sat, Oct 24, 2009 at 10:04 AM, brem belguebli
> > <brem.belguebli at gmail.com>wrote:
> >
> >> It's non sense arguing that LVM is not intended for root due to the
> >> fact that you cannot shrink it  (growing online is operational and
> >> works fine).
> >>
> >> This is the only thing that is not allowed, though technically could
> >> it be possible.
> >>
> >>
> >>
> >> 2009/10/24, Lou Arnold <larnolda1 at gmail.com>:
> >>  > Haha, Yes, it would have been nice for someone to have told me about
> >> LVM and
> >> > root. It would have saved literally days of time. But my work is
> >> > experimental and never with production system. In any case, now I know
> >> > better.
> >> >
> >> > As for the LiveCD suggestion, I did not intend to discount it. I had
> in
> >> fact
> >> > tried it several times, but with  some success. It probably just a
> >> > matter
> >> of
> >> > finger problems for the failures. But I truly expected a graceful
> >> > dismantling process without the need of shutting down the system.
> >> >
> >> > This was in fact a good experience. When you have to dig into things
> to
> >> > understand why something works or doesn't work, you are always luckier
> >> than
> >> > if things go perfectly right from the beginning.
> >> >
> >> > Thanks to everyone for your help.
> >> > Lou.
> >> >
> >> >
> >> >
> >> > On Fri, Oct 23, 2009 at 5:06 PM, Brian McCullough <bdmc at bdmcc-us.com>
> >> wrote:
> >> >
> >> >> On Fri, Oct 23, 2009 at 01:41:23PM -0700, Lou Arnold wrote:
> >> >> > Ryan, Thanks for your suggestion. I know it works, but I had hoped
> to
> >> >> have a
> >> >> > solution that didn't stop the whole system while I fixed it.
> >> >> >
> >> >> > To Drew:
> >> >> > I think you were quite right when you spoke about planning the file
> >> >> system.
> >> >> > I've come to realize that my question is somewhat naive. One simply
> >> >> doesn't
> >> >> > do what I wanted to exactly because there is no easy way to
> dismantle
> >> >> > it.
> >> >> It
> >> >> > would be better to partition off some part of the OS drive and add
> >> that
> >> >> to a
> >> >> > new volume group (or a new logical volume group) and mount that
> under
> >> >> > "/mnt", and then add whatever partitions on new drives to that
> >> >> > logical
> >> >> > volume. That logical volume could be dismounted and worked on,
> >> >> > whereas
> >> >> > whatever is under root cannot be worked on easily.
> >> >>
> >> >>
> >> >> Lou,
> >> >>
> >> >> I'm surprised that you haven't yet been told that one of the first
> >> >> rules
> >> >> of
> >> >> LVM is "don't use it for root!"  Actually, I don't really hold with
> >> that,
> >> >> but it is MUCH more important to plan what you are doing when you do
> >> have
> >> >> an
> >> >> LVM root partition.  As you have found, you can not manipulate an LVM
> >> >> partition while it is mounted. ( I know, there are ways for certain
> >> types
> >> >> of
> >> >> filesystems, but in general, the rule holds. )  That is especially
> true
> >> >> when
> >> >> the partition that you want to manipulate is root ( / ).
> >> >>
> >> >> My general practice is to set up the following list of Logical
> Volumes
> >> >> (
> >> >> the minimum which serves for most general purpose machines ): root,
> >> swap,
> >> >> home, usr, var.  I generally allocate somewhere around 1G for the
> root
> >> >> partition.  The others are sized appropriately for the environment.
> >>  That
> >> >> usually leaves me a lot of free space on modern drives for "data"
> >> >> space.
> >> >>
> >> >> The recommendation that you should find a LiveCD at this point is
> >> probably
> >> >> one that you should respect.  Playing with mounted filesystems,
> >> >> particularly
> >> >> root, can rapidly lead you down a very nasty path.
> >> >>
> >> >>
> >> >> Brian
> >> >>
> >> >> _______________________________________________
> >> >> linux-lvm mailing list
> >> >> linux-lvm at redhat.com
> >> >> https://www.redhat.com/mailman/listinfo/linux-lvm
> >> >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> >> >>
> >> >
> >>
> >> _______________________________________________
> >> linux-lvm mailing list
> >> linux-lvm at redhat.com
> >> https://www.redhat.com/mailman/listinfo/linux-lvm
> >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> >>
> >
>
> _______________________________________________
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
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