[linux-lvm] Allocation maps of a mirrored LV?

[linux-lvm] Allocation maps of a mirrored LV?

[Lupe Christoph]

Hi!

I'm about to integrate support for LVM mirrors into the configuration
management system I'm maintaining for a client. This system has a "scan"
function that retrieves the current configuration and compares it
against a database.

My problem is that I'm unable to get the allocation info for the parts
of a mirrored volume under SLES 10 (lvm2 RPM is at 2.02.17, even
OpenSuSE 10.3 has only lvm2 2.02.25).

lvdisplay --maps only gives me:

  --- Segments ---
  Logical extent 0 to 24:
    Type		mirror
    Mirrors		2
    Mirror size		25
    Mirror log volume	testlv0_mlog
    Mirror region size	512.00 KB
    Mirror original:
      Logical volume	testlv0_mimage_0
      Logical extents	0 to 24
    Mirror destinations:
      Logical volume	testlv0_mimage_1
      Logical extents	0 to 24

This is lacking the names of the PVs. (Has this been implemented in the
meantime? It would be useful - nudge, nudge...)

BTW, a simple volume *has* this information:

  --- Segments ---
  Logical extent 0 to 31:
    Type		linear
    Physical volume	/dev/sda3
    Physical extents	1261 to 1292

I'm unable to convince lvdisplay to give me any information on, e.g.,
testlv0_mimage_0. And pvdisplay --maps does not display allocation maps
up to 2.02.27, AFAIK.

So does anybody have a way to find out on which PV the mirror parts are?
Short of installing our own lvm2 RPM, of course. Or parsing the raw LVM
config info on the disks...

Thanks for any hint,
Lupe Christoph
-- 
| There is no substitute for bad design except worse design.             |
| /me                                                                    |

Re: [linux-lvm] Allocation maps of a mirrored LV?

[David Robinson]

On Tue, Jan 13, 2009 at 10:09 AM, Lupe Christoph <lupe@lupe-christoph.de> wrote:
> Hi!
>
> I'm about to integrate support for LVM mirrors into the configuration
> management system I'm maintaining for a client. This system has a "scan"
> function that retrieves the current configuration and compares it
> against a database.
>
> My problem is that I'm unable to get the allocation info for the parts
> of a mirrored volume under SLES 10 (lvm2 RPM is at 2.02.17, even
> OpenSuSE 10.3 has only lvm2 2.02.25).
>
> lvdisplay --maps only gives me:

Try pvs/vgs/lvs instead (and use -o to get the details you want):

# pvs --segments
  PV         VG     Fmt  Attr PSize  PFree  Start SSize
  /dev/dm-0  laptop lvm2 a-   55.69G 32.00M     0   250
  /dev/dm-0  laptop lvm2 a-   55.69G 32.00M   250  1499
  /dev/dm-0  laptop lvm2 a-   55.69G 32.00M  1749    32
  /dev/dm-0  laptop lvm2 a-   55.69G 32.00M  1781     1

--Dave

Re: [linux-lvm] Allocation maps of a mirrored LV?

[Lupe Christoph]

On Wednesday, 2009-01-14 at 20:58:28 +0000, David Robinson wrote:
> On Tue, Jan 13, 2009 at 10:09 AM, Lupe Christoph <lupe@lupe-christoph.de> wrote:

> > I'm about to integrate support for LVM mirrors into the configuration
> > management system I'm maintaining for a client. This system has a "scan"
> > function that retrieves the current configuration and compares it
> > against a database.

> > My problem is that I'm unable to get the allocation info for the parts
> > of a mirrored volume under SLES 10 (lvm2 RPM is at 2.02.17, even
> > OpenSuSE 10.3 has only lvm2 2.02.25).

> > lvdisplay --maps only gives me:

> Try pvs/vgs/lvs instead (and use -o to get the details you want):

> # pvs --segments
>   PV         VG     Fmt  Attr PSize  PFree  Start SSize
>   /dev/dm-0  laptop lvm2 a-   55.69G 32.00M     0   250
>   /dev/dm-0  laptop lvm2 a-   55.69G 32.00M   250  1499
>   /dev/dm-0  laptop lvm2 a-   55.69G 32.00M  1749    32
>   /dev/dm-0  laptop lvm2 a-   55.69G 32.00M  1781     1

OK, let me show you. I created an LV with:
lvcreate --name testlv0 --size 100m --mirror 1 testvg

lvs -o +devices
  LV              VG     Attr   LSize   Origin Snap%  Move Log          Copy%  Devices
  testlv0         testvg mwi-a- 100.00M                    testlv0_mlog 100.00 testlv0_mimage_0(0),testlv0_mimage_1(0)

Any other suggestion for a -o option? I tried stripes, segtype, seg_start,
seg_size, seg_tags, regionsize, mirror_log and lvs --segments.

I can't find an option for pvs that prints the allocation map, nor for
vgs. Any suggestions?

Lupe Christoph
-- 
| There is no substitute for bad design except worse design.                   |
| /me                                                                          |

Re: [linux-lvm] Allocation maps of a mirrored LV?

[Jaroslav Stava]

Lupe Christoph wrote:
> I can't find an option for pvs that prints the allocation map, nor for
> vgs. Any suggestions?
>   
Try
lvs VG -a --segments -o +devices
that should print all the information you need.

Regards,
Jaroslav Stava

Re: [linux-lvm] Allocation maps of a mirrored LV?

[Lupe Christoph]

On Thursday, 2009-01-15 at 10:30:27 +0100, Jaroslav Stava wrote:
> Lupe Christoph wrote:
>> I can't find an option for pvs that prints the allocation map, nor for
>> vgs. Any suggestions?

> Try
> lvs VG -a --segments -o +devices
> that should print all the information you need.

<hug>Jaroslav, you're right!</hug>

Actually, I don't need segment information, so I can omit --segment. The
command that gives me what I can use is

lvs testvg --separator : --noheadings --all -o +devices

The "-a" or "--all" option is the key. Thanks a lot for this! Now that I
know what to look for, I find it in lvs --help. But not in the manpages.
Guess where I looked :-(

Lupe Christoph
-- 
| There is no substitute for bad design except worse design.                   |
| /me                                                                          |