[DRBD-user] Filesystem inside a XEN dom-u

[Michael Grant]

On Wed, Jan 21, 2009 at 6:04 PM, Daniel <dh at dimax-it.de> wrote:
> I all,
>
> i tried to configure a virtual device inside a xen.
> Here my short config vom drbd.conf:
>
> global {
>  usage-count yes;
> }
> common {
>  protocol C;
> }
> resource r0 {
>  on sql1 {
>    device    /dev/drbd1;
>    disk      /dev/hda3;
>    address   193.34.120.13:7789;
>    meta-disk internal;
>  }
>  on sql2 {
>    device    /dev/drbd1;
>    disk      /dev/hda3;
>    address   193.34.120.14:7789;
>    meta-disk internal;
>  }
> }
>
> When i try do create i disk i get the following error:
>
> sql1:~# drbdadm create-md r0
> md_offset 2097147904
> al_offset 2097115136
> bm_offset 2097049600
>
> Found ext3 filesystem which uses 2048000 kB
> current configuration leaves usable 2047900 kB
>
> Device size would be truncated, which
> would corrupt data and result in
> 'access beyond end of device' errors.
> You need to either
>   * use external meta data (recommended)
>   * shrink that filesystem first
>   * zero out the device (destroy the filesystem)
> Operation refused.
>
> Command 'drbdmeta /dev/drbd1 v08 /dev/hda3 internal create-md' terminated with exit code 40
> drbdadm aborting
>
>
> Is XEN unable to manage that or is there something wrong?
> the drbd kernel modul is already loaded.
>
> would be nice to hear from u ;)
>
> greetz

You already have a file system in r0, so you'll either need to grow
the lv or shrink the file system in it to make space for the metadata.
 This link tells you how much metadata is needed
http://www.drbd.org/users-guide-emb/ch-internals.html#s-meta-data-size.
 Or you can put your meta data outside the file system.