Re: [linux-lvm] Why didn't the lv extension go through even if lvdisplay says so?

[Patrick Caulfield <pcaulfie@redhat.com>]

Marcus Claesson wrote:
> Hi all,
> 
> I want to allocate 140G of the free space in my VG and use it to
> extend /var (/dev/Volume00/LogVol01) from 97G to 240G. After I
> unmounted /var (which was impossible until I used a lazy 'umount -
> l /var'), I ran
> 
> # lvextend -L 240G /dev/Volume00/LogVol01
> (unfortunately I was in single-user mode and wasn't able to save the
> output, but it basically said 'extension successful). I then re-
> mounted /var:
> 
> # mount /dev/mapper/Volume00-LogVol01 /var/
> kjournald starting.  Commit interval 5 seconds
> EXT3 FS on dm-2, internal journal
> EXT3-fs: mounted filesystem with ordered data mode.
> 
> and ran a df to check:
> 
> # df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/cciss/c0d0p2      49G   19G   27G  42% /
> /dev/cciss/c0d0p1      99M  9.8M   84M  11% /boot
> /dev/mapper/Volume00-LogVol00
>                        97G   84G  8.1G  92% /home
> none                  2.9G     0  2.9G   0% /dev/shm
> /dev/mapper/Volume00-LogVol02
>                        20G   11G  8.4G  56% /usr/local
> sunrpc                 97G   88G  3.6G  97% /var/lib/nfs/rpc_pipefs
> /dev/mapper/Volume00-LogVol01
>                        97G   88G  3.6G  97% /var
> 
> To my surprise /var hadn't been extended at all and a new sunrpc device
> had also been mounted! The lvm info is now:
> 
> # vgdisplay
>   --- Volume group ---
>   VG Name               Volume00
>   System ID             localhost.localdomain1077884666
>   Format                lvm1
>   VG Access             read/write
>   VG Status             resizable
>   MAX LV                256
>   Cur LV                3
>   Open LV               3
>   Max PV                256
>   Cur PV                1
>   Act PV                1
>   VG Size               496.02 GB
>   PE Size               4.00 MB
>   Total PE              126981
>   Alloc PE / Size       91560 / 357.66 GB
>   Free  PE / Size       35421 / 138.36 GB
>   VG UUID               H0hRDH-Ud2L-fYSG-j1mE-3QfB-5xMo-3Sb6Mf
> 
> Thus 240G has been used up.
> 
> # lvdisplay
>   --- Logical volume ---
>   LV Name                /dev/Volume00/LogVol01
>   VG Name                Volume00
>   LV UUID                000000-0000-0000-0000-0000-0000-000002
>   LV Write Access        read/write
>   LV Status              available
>   # open                 1
>   LV Size                240.00 GB
>   Current LE             61440
>   Segments               1
>   Allocation             normal
>   Read ahead sectors     10000
>   Block device           253:2
> 
> Thus new size as it should be.
> 
> Also, the difference between the current and old VG is:
> # diff /etc/lvm/backup/Volume00 /etc/lvm/archive/Volume00_00004.vg
> 1c1
> < # Generated by LVM2: Tue May 16 12:27:42 2006
> ---
>> # Generated by LVM2: Tue May 16 12:24:15 2006
> 6c6
> < description = "Created *after* executing 'vgdisplay'"
> ---
>> description = "Created *before* executing 'lvextend -L 240G -
> v /dev/Volume00/LogVol01'"
> 9c9
> < creation_time = 1147778862    # Tue May 16 12:27:42 2006
> ---
>> creation_time = 1147778655    # Tue May 16 12:24:15 2006
> 83c83
> <                               extent_count = 61440    # 240 Gigabytes
> ---
>>                               extent_count = 25000    # 97.6562
> Gigabytes
> 
> The whole new /etc/lvm/backup/Volume00 is
> 
> # cat /etc/lvm/backup/Volume00
> # Generated by LVM2: Tue May 16 12:27:42 2006
> 
> contents = "Text Format Volume Group"
> version = 1
> 
> description = "Created *after* executing 'vgdisplay'"
> 
> creation_host = "neo.ucc.ie"    # Linux neo.ucc.ie 2.6.9-34.ELsmp #1 SMP
> Fri Feb 24 16:54:53 EST 2006 i686
> creation_time = 1147778862      # Tue May 16 12:27:42 2006
> 
> Volume00 {
>         id = "H0hRDH-Ud2L-fYSG-j1mE-3QfB-5xMo-3Sb6Mf"
>         seqno = 0
>         status = ["RESIZEABLE", "READ", "WRITE"]
>         system_id = "localhost.localdomain1077884666"
>         extent_size = 8192              # 4 Megabytes
>         max_lv = 256
>         max_pv = 256
> 
>         physical_volumes {
> 
>                 pv0 {
>                         id = "xXbxiu-uog2-xSRe-dI2z-y2ZQ-9weE-ftY6YL"
>                         device = "/dev/cciss/c0d0p5"    # Hint only
> 
>                         status = ["ALLOCATABLE"]
>                         pe_start = 9472
>                         pe_count = 126981       # 496.02 Gigabytes
>                 }
>         }
> 
>         logical_volumes {
> 
>                 LogVol00 {
>                         id = "000000-0000-0000-0000-0000-0000-000000"
>                         status = ["READ", "WRITE", "VISIBLE"]
>                         allocation_policy = "normal"
>                         read_ahead = 10000
>                         segment_count = 1
> 
>                         segment1 {
>                                 start_extent = 0
>                                 extent_count = 25000    # 97.6562
> Gigabytes
> 
>                                 type = "striped"
>                                 stripe_count = 1        # linear
> 
>                                 stripes = [
>                                         "pv0", 0
>                                 ]
>                         }
>                 }
> 
>                 LogVol02 {
>                         id = "000000-0000-0000-0000-0000-0000-000001"
>                         status = ["READ", "WRITE", "VISIBLE"]
>                         allocation_policy = "normal"
>                         read_ahead = 10000
>                         segment_count = 1
> 
>                         segment1 {
>                                 start_extent = 0
>                                 extent_count = 5120     # 20 Gigabytes
> 
>                                 type = "striped"
>                                 stripe_count = 1        # linear
> 
>                                 stripes = [
>                                         "pv0", 25000
>                                 ]
>                         }
>                 }
> 
>                 LogVol01 {
>                         id = "000000-0000-0000-0000-0000-0000-000002"
>                         status = ["READ", "WRITE", "VISIBLE"]
>                         allocation_policy = "normal"
>                         read_ahead = 10000
>                         segment_count = 1
> 
>                         segment1 {
>                                 start_extent = 0
>                                 extent_count = 61440    # 240 Gigabytes
> 
>                                 type = "striped"
>                                 stripe_count = 1        # linear
> 
>                                 stripes = [
>                                         "pv0", 50000
>                                 ]
>                         }
>                 }
>         }
> }
> 
> 
> 
> How come the size extension didn't go through?
> 
> Any hints are much appreciated!


It has been extended, you need to extend the filesystem too:

See the LVM HOWTO at

http://www.tldp.org/HOWTO/LVM-HOWTO/extendlv.html
-- 

patrick