cant mount second drive

[Rick Stevens]

On Thu, 2007-01-18 at 18:03 -0800, Rick Stevens wrote:
> On Thu, 2007-01-18 at 20:44 -0500, jack wallen wrote:
> > On Fri, 2007-01-19 at 09:15 +0800, Ed Greshko wrote:
> > 
> > > Please run "parted" and print the partition table as root.  For example...
> > > In your case, it will be /dev/hdb...of course.
> > 
> > oddly enough i'm getting:
> > 
> > Model: SAMSUNG SP0411N (ide)
> > Disk /dev/hdb: 40.1GB
> > Sector size (logical/physical): 512B/512B
> > Partition Table: msdos
> > 
> > Number  Start   End     Size    Type     File system  Flags
> >  1      32.3kB  107MB   107MB   primary  ext3         boot
> >  2      107MB   40.1GB  40.0GB  primary               lvm
> > 
> > why is the File System on the lvm partition not coming up?
> > 
> > i know it was partitioned as an ext3 file system under FC6.
> 
> parted looks at _physical_ volumes only and a filesystem can only be
> shown if the entire volume is in play.  Remember that a logical volume
> is made of chunks of the volume group--and those chunks could be on
> different physical volumes.  lvm stitches them together.  Since parted
> doesn't talk to the LVM layer, it can't see the filesystem.
> 
> I hope that explains it.

Whoops!  I also should have said that that's why the "fsck /dev/hdb2"
failed...hdb2 isn't an ext3 filesystem...it's the low level thing that
the LVM-based ext3 filesystem is built on.  You'd have to run the fsck
against the /dev/mapper/vgname-lvname device to bring LVM into play.
For example, the actual device making up my /usr filesystem is
/dev/mapper/sys_vg-usr_lv.  It's made up of chunks of the sys_vg volume
group.  Other chunks of the sys_vg volume group make up my /, /home,
/var and swap filesystems:

[root at golem2 ~]# lvdisplay
  --- Logical volume ---
  LV Name                /dev/sys_vg/root_lv
  VG Name                sys_vg
  LV UUID                9IznKZ-7CXS-ifiP-pBn1-UZEP-FVG5-A4FWoF
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                4.00 GB
  Current LE             128
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0
   
  --- Logical volume ---
  LV Name                /dev/sys_vg/home_lv
  VG Name                sys_vg
  LV UUID                BG1xHJ-wIA4-x2ch-VTjO-l2T2-UJQB-qtQ1Ea
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                8.00 GB
  Current LE             256
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:1
   
  --- Logical volume ---
  LV Name                /dev/sys_vg/usr_lv
  VG Name                sys_vg
  LV UUID                RV0DQW-t95g-KV7v-ufL6-gt34-plKd-HmzI3d
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                91.50 GB
  Current LE             2928
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:2
   
  --- Logical volume ---
  LV Name                /dev/sys_vg/var_lv
  VG Name                sys_vg
  LV UUID                xhlaZy-XK4N-vHF7-KoQk-3k6Y-0nXP-VMT8cU
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                4.00 GB
  Current LE             128
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:3
   
  --- Logical volume ---
  LV Name                /dev/sys_vg/swap_lv
  VG Name                sys_vg
  LV UUID                ulRHpF-CISK-rO1q-39Yw-Tc7B-2xmW-iDkxWC
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                4.00 GB
  Current LE             128
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:4

[root at golem2 ~]# vgdisplay
  --- Volume group ---
  VG Name               sys_vg
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                5
  Open LV               5
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               111.53 GB
  PE Size               32.00 MB
  Total PE              3569
  Alloc PE / Size       3568 / 111.50 GB
  Free  PE / Size       1 / 32.00 MB
  VG UUID               cJYqjz-NKht-cmEf-5Kzf-GxVG-P1hn-nI5ivV

[root at golem2 ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/hda2
  VG Name               sys_vg
  PV Size               111.53 GB / not usable 0   
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              3569
  Free PE               1
  Allocated PE          3568
  PV UUID               ecTyyn-waBk-HSIN-eMDZ-fLQX-KX1h-zMw0od


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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-   You possess a mind not merely twisted, but actually sprained.    -
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