[DRBD-user] DRBD 0.7.5 & LVM2 on 2.4.27

Tim Hasson tim at aidasystems.com
Tue Oct 5 14:26:49 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Quoting Lars Ellenberg <Lars.Ellenberg at linbit.com>,
on Tue, 5 Oct 2004 02:25:47 +0200:

> / 2004-10-04 16:46:16 -0700
> \ Tim Hasson:
> > [root at srv1 root]# cat /etc/ha.d/haresources
> > srv1.aidasystems.com \
> > \
> >         drbddisk::all \
> >         lvm2 \
> >         Filesystem::/dev/Volume0/LogVol0::/data::ext3::usrquota
> unfortunately, this does not work properly:
> heartbeat likes to call "status" often, and
>   drbddisk all status
> is not implemented, and does not make much sense from the heartbeat
> perspective, either.  so, from the heartbeat perspective, drbddisk all
> status will always report the resources as stopped...
> so better use drbddisk::r0 drbddisk::r1

Thanks for the note! I will modify my haresources file accordingly.
Though, I did not run into any problems nor seen any weird things in ha-log
(after overnight burn-in test, I think)

>From your pre-last message, you mentioned:

> > > to simplify management, you could put a linear mapping on both
> > > lower level devices first, then put drbd on top of that linear mapping,
> > > and then put your lvm2 vg on top of that single drbd.
> > > but then don't use "drbd internal meta data" on that, if you think about
> > > later maybe adding more harddisks to the lower linear mapping and
> > > resizing the drbd device.
> > > but maybe "just a wrapper script" will do, too.

What do you mean by "just a wrapper script" will do? and do what?

> I thought about something like this:
> ll_dev0=/dev/ll_dev_of_drbd0
> ll_dev1=/dev/ll_dev_of_drbd1
> size_of_ll0=$(fdisk -s $ll_dev0)
> size_of_ll1=$(fdisk -s $ll_dev1)
> echo "\
> 0 $[size_of_ll0<<1] linear $ll_dev0 0
> $[size_of_ll0<<1] $[size_of_ll1<<1] linear $ll_dev1 0" |
> 	dmsetup create ll_linear_for_drbd
> drbd.conf: disk /dev/mapper/ll_linear_for_drbd

Just did man dmsetup. Very interesting, and a great suggestion btw.

But, suppose I wanted to retire one or both of my old disks.
With LVM2, I can do "pvmove" (which requires dm-mirror in kernel/as module)
There's also helper tools such as vgreduce and vgextend which aid in the disk
subsituting process ( http://www.tldp.org/HOWTO/LVM-HOWTO/removeadisk.html )

Is this still possible with the dm linear mapping setup?

>From dmsetup (8) manpage:
There are currently three simple target types available together with more
complex optional ones that implement snapshots and mirrors.

Also, could I still do online resizing when adding disks to the lower linear


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