Dear,

I recently set up a spare hdd with LVM2. I happen not to have partitionned the disk with LV sizes suitable for my environment, but LVM is supposed to help make those changes a breeze right???

Ok so basically when I do:

bash-3.1# vgdisplay
--- Volume group ---
VG Name my_vg_name
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 8
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 17.12 GB
PE Size 4.00 MB
Total PE 4384
Alloc PE / Size 4352 / 17.00 GB
Free PE / Size 1332 / 5.12 GB
VG UUID CLj3Qx-SoIh-j2Ls-vCkt-T13V-eTYA-5Kz5ct

Which is about right (supposed to be 18G hdd though).

What happens is that the disk was actually setup with 3 LVs at first. I tried to reduce the third LV so that I could then extend the the second LV but this didn't work, so I lvremoved the third LV.

Then:

lvextend -L+3G /dev/my_vg/my_logical_volume#2
Extending logical volume lvm2 to 9.00 GB
Insufficient free space: 2304 extents needed, but only 1312 available

Which makes sense half way since 2304 extents are needed but only 1312 are available. Though vgdisplay clearly states that there is 5.12GB left free on the disk...

Let's try to recreate a third LV:

lvcreate -L5G -n my_logical_volume#3 my_volume_group
Logical volume "my_logical_volume#3" created

And again:

vgdisplay
--- Volume group ---
VG Name my_vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 8
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 17.12 GB
PE Size 4.00 MB
Total PE 4384
Alloc PE / Size 4352 / 17.00 GB
Free PE / Size 32 / 128.00 MB
VG UUID CLj3Qx-SoIh-j2Ls-vCkt-T13V-eTYA-5Kz5ct


By comparing the output of vgdisplay, you can see that creating a new LV of 5G uses 1300 PEs but extending an existing LV requires 2304 PEs, however. Is this how it is suposed to work or am I doing things the wrong way around? The LVM-howto also states that there are different mapping modes (linear/stripped) but I haven't got my head around this yet, could that be the source of the problem??

Any advice appreciated. Thanks

This is the version of LVM that I downloded tried first 2.02.13 from linuxpackages. It must be buggy since after downloading a more recent version and compiled it from source it works ok...

Why don't you use the official Slackware version?

Do you mean the one that comes installed with Slackware? Because I run 2.6 kernel...

Yes, me too.
There's an LVM2 package on the CDs/DVD that works wonderfully with the 2.6 kernel.

Sorry but, do you mean on the slackware CDs/DVDs???

Yes, it's on the official Slackware CDs/DVD.
On my favorite mirror, you can download from here.