[linux-lvm] LVM questions & problems.

[linux-lvm] LVM questions & problems.

[Rupert Heesom]

I'm practicing doing some LVM commands, and am coming up with some
problems -

Most disconcerting is that when I try to create a directory in the LV, I
get the following error - (this does not happen all the time, but almost
all the time 99%) -

[root@localhost Tmp]# mkdir test1
mkdir: cannot create directory `test1': Input/output error

Creating normal files on the LV is not a problem.

Also, the figures in the following outputs don't seem to make sense to
me -

287Mb of space taken on my LV lvol1 (shown using du -h).

LV lvol1 - shows all 75 logical extends taken, I'm assuming filling up
the 300Mb LV size.

LV Size                300 MB
Current LE             75
Allocated LE           75


PV shows too many physical extends used for the proportion of disk space
used. -

Total PE              76
Free PE               1

PVdisplay shows too many physical extents used again

Total PE              76
Free PE               1
Allocated PE          75


----------------------------------------

LVM command outputs
-------------------

[root@localhost Tmp]# lvdisplay /dev/vg/lvol1
lvdisplay
--- Logical volume ---
LV Name                /dev/vg/lvol1
VG Name                vg
LV Write Access        read/write
LV Status              available
LV #                   1
# open                 1
LV Size                300 MB
Current LE             75
Allocated LE           75
Allocation             next free
Read ahead sectors     120
Block device           58:0


[root@localhost Tmp]# pvdisplay /dev/sdb1
pvdisplay
--- Physical volume ---
PV Name               /dev/sdb1
VG Name               vg
PV Size               305.89 MB / NOT usable 1.89 MB [LVM: 121 KB]
PV#                   1
PV Status             available
Allocatable           yes
Cur LV                1
PE Size (KByte)       4096
Total PE              76
Free PE               1
Allocated PE          75
PV UUID               wm3nGp-pEem-0byC-3JOs-OFs4-3kv2-EkPxaK


[root@localhost Tmp]# vgdisplay
vgdisplay
--- Volume group ---
VG Name               vg
VG Access             read/write
VG Status             available/resizable
VG #                  0
MAX LV                256
Cur LV                1
Open LV               1
MAX LV Size           255.99 GB
Max PV                256
Cur PV                1
Act PV                1
VG Size               304 MB
PE Size               4 MB
Total PE              76
Alloc PE / Size       75 / 300 MB
Free  PE / Size       1 / 4 MB
VG UUID               0ZyZNT-53L9-tAFJ-GCa4-1Zr5-nZli-IFIbIP


-- 
regs
rupert

Re: [linux-lvm] LVM questions & problems.

[Heinz J. Mauelshagen]

On Sun, May 06, 2001 at 09:05:13PM -0400, Rupert Heesom wrote:
> I'm practicing doing some LVM commands, and am coming up with some
> problems -
> 
> Most disconcerting is that when I try to create a directory in the LV, I
> get the following error - (this does not happen all the time, but almost
> all the time 99%) -
> 
> [root@localhost Tmp]# mkdir test1
> mkdir: cannot create directory `test1': Input/output error

You didn't metion, if the filesystem is still in a sane state.

Did you check your syslog for "accessess beyond the end of the device"
which indicate fs related problems?

If so: did you run fsck to fix those and did you retest?

> 
> Creating normal files on the LV is not a problem.
> 
> Also, the figures in the following outputs don't seem to make sense to
> me -
> 
> 287Mb of space taken on my LV lvol1 (shown using du -h).

du is a filesystem tool which tells you how much space is used
from the fs perspective.
The LV tools provide information from the underlying block device being
exposed by the LVM to the filesytem or other users (like databases etc.).

> 
> LV lvol1 - shows all 75 logical extends taken, I'm assuming filling up
> the 300Mb LV size.
> 
> LV Size                300 MB
> Current LE             75
> Allocated LE           75

O.k.
That shows, that you have a 300M logical volume, which you said above.

vgdisplay on your volume group gives you (beside other information)
the size of the physical extents (PEs) which is 4M by default.

You can change that in order to address bigger configurations with
"vgcreate -s". Please see "man vgcreate" for further details.

> 
> 
> PV shows too many physical extends used for the proportion of disk space
> used. -
> 
> Total PE              76
> Free PE               1

That's ok because you allocated 75PEs which are 300M based on
4M PE size.

> 
> PVdisplay shows too many physical extents used again
> 
> Total PE              76
> Free PE               1
> Allocated PE          75

Same as above.


Please have a look at the LVM howto at www.sistina.com/lvm
for further hints on LVM usage.


Regards,
Heinz    -- The LVM Guy --


> 
> 
> ----------------------------------------
> 
> LVM command outputs
> -------------------
> 
> [root@localhost Tmp]# lvdisplay /dev/vg/lvol1
> lvdisplay
> --- Logical volume ---
> LV Name                /dev/vg/lvol1
> VG Name                vg
> LV Write Access        read/write
> LV Status              available
> LV #                   1
> # open                 1
> LV Size                300 MB
> Current LE             75
> Allocated LE           75
> Allocation             next free
> Read ahead sectors     120
> Block device           58:0
> 
> 
> [root@localhost Tmp]# pvdisplay /dev/sdb1
> pvdisplay
> --- Physical volume ---
> PV Name               /dev/sdb1
> VG Name               vg
> PV Size               305.89 MB / NOT usable 1.89 MB [LVM: 121 KB]
> PV#                   1
> PV Status             available
> Allocatable           yes
> Cur LV                1
> PE Size (KByte)       4096
> Total PE              76
> Free PE               1
> Allocated PE          75
> PV UUID               wm3nGp-pEem-0byC-3JOs-OFs4-3kv2-EkPxaK
> 
> 
> [root@localhost Tmp]# vgdisplay
> vgdisplay
> --- Volume group ---
> VG Name               vg
> VG Access             read/write
> VG Status             available/resizable
> VG #                  0
> MAX LV                256
> Cur LV                1
> Open LV               1
> MAX LV Size           255.99 GB
> Max PV                256
> Cur PV                1
> Act PV                1
> VG Size               304 MB
> PE Size               4 MB
> Total PE              76
> Alloc PE / Size       75 / 300 MB
> Free  PE / Size       1 / 4 MB
> VG UUID               0ZyZNT-53L9-tAFJ-GCa4-1Zr5-nZli-IFIbIP
> 
> 
> -- 
> regs
> rupert
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM questions & problems.

[Rupert Heesom]

On 07 May 2001 10:28:44 +0000, Heinz J. Mauelshagen wrote:
> On Sun, May 06, 2001 at 09:05:13PM -0400, Rupert Heesom wrote:
> > I'm practicing doing some LVM commands, and am coming up with some
> > problems -
> > 
> > Most disconcerting is that when I try to create a directory in the LV, I
> > get the following error - (this does not happen all the time, but almost
> > all the time 99%) -
> > 
> > [root@localhost Tmp]# mkdir test1
> > mkdir: cannot create directory `test1': Input/output error
> 
> You didn't metion, if the filesystem is still in a sane state.
> 
> Did you check your syslog for "accessess beyond the end of the device"
> which indicate fs related problems?

Well, looking at my syslog after mounting my lvol, I saw the following
msg -

"May  7 11:51:26 localhost kernel: EXT2-fs warning: mounting fs with
errors, running e2fsck is recommended"

I also saw previous errors which you asked about (lots of them) -

"itmap: Cannot read inode bitmap - block_group = 3, inode_bitmap = 98307
May  6 14:44:13 localhost kernel: attempt to access beyond end of
device...."

I have realised what my base problem is.... I have reduced the LV size,
but not reduced the Ext2 filesystem.  For some reason I thought that
resizing the LV was sufficient.  Looking further at the HOWTO, and other
web docs has enlightened me further.

It seems I will try to learn how to use teh e2fsadm util.  BTW one of
the utils seems to be commercial from Powerquest.  I have the v4 of
Partition Magic already.  I know it resizes ext2 filesystems, but as far
as I know needs to be run from within windows (it's been a long time
since I've used it last).  Are the utils such as e2fsadm sufficient /
good enough without the commercial PM util?



-- 
regs
rupert

Re: [linux-lvm] LVM questions & problems.

[Heinz J. Mauelshagen]

On Mon, May 07, 2001 at 11:57:03AM -0400, Rupert Heesom wrote:
> On 07 May 2001 10:28:44 +0000, Heinz J. Mauelshagen wrote:
> > On Sun, May 06, 2001 at 09:05:13PM -0400, Rupert Heesom wrote:
> > > I'm practicing doing some LVM commands, and am coming up with some
> > > problems -
> > > 
> > > Most disconcerting is that when I try to create a directory in the LV, I
> > > get the following error - (this does not happen all the time, but almost
> > > all the time 99%) -
> > > 
> > > [root@localhost Tmp]# mkdir test1
> > > mkdir: cannot create directory `test1': Input/output error
> > 
> > You didn't metion, if the filesystem is still in a sane state.
> > 
> > Did you check your syslog for "accessess beyond the end of the device"
> > which indicate fs related problems?
> 
> Well, looking at my syslog after mounting my lvol, I saw the following
> msg -
> 
> "May  7 11:51:26 localhost kernel: EXT2-fs warning: mounting fs with
> errors, running e2fsck is recommended"
> 
> I also saw previous errors which you asked about (lots of them) -
> 
> "itmap: Cannot read inode bitmap - block_group = 3, inode_bitmap = 98307
> May  6 14:44:13 localhost kernel: attempt to access beyond end of
> device...."
> 
> I have realised what my base problem is.... I have reduced the LV size,
> but not reduced the Ext2 filesystem.  For some reason I thought that
> resizing the LV was sufficient.

It likely will be at some point in time in the future.
Triggering the fs resize when a LN gets resized is a TODO item :-)

> Looking further at the HOWTO, and other
> web docs has enlightened me further.
> 
> It seems I will try to learn how to use teh e2fsadm util.  BTW one of
> the utils seems to be commercial from Powerquest.  I have the v4 of
> Partition Magic already.  I know it resizes ext2 filesystems, but as far
> as I know needs to be run from within windows (it's been a long time
> since I've used it last).  Are the utils such as e2fsadm sufficient /
> good enough without the commercial PM util?

You need to get the resize2fs tool (by Ted Ts'o and Powerquest) in order
to run e2fsadm.

e2fsadm basically is a wrapper which runs either

   e2fsck;lvextend;resize2fs

or

   e2fsck;resize2fs;lvreduce


resize2fs might already be contained in your distribution.

If not so, use for eg. ftpsearch.lycos.com to figure piles of spaces
where to get it.

> 
> -- 
> regs
> rupert
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM questions & problems.

[Andreas Dilger]

Heinz writes:
> On Mon, May 07, 2001 at 11:57:03AM -0400, Rupert Heesom wrote:
> > It seems I will try to learn how to use teh e2fsadm util.  BTW one of
> > the utils seems to be commercial from Powerquest.  I have the v4 of
> > Partition Magic already.  I know it resizes ext2 filesystems, but as far
> > as I know needs to be run from within windows (it's been a long time
> > since I've used it last).  Are the utils such as e2fsadm sufficient /
> > good enough without the commercial PM util?
> 
> You need to get the resize2fs tool (by Ted Ts'o and Powerquest) in order
> to run e2fsadm.
> 
> resize2fs might already be contained in your distribution.

If you have e2fsprogs 1.19 then it contains resize2fs.  The deal Ted had
with Powerquest is that resize2fs would become GPL after 2 years or so.

The e2fsadm program can use ext2resize (http://ext2resize.sourceforge.net)
instead of resize2fs.  If you patch your kernel with the ext2online patch,
then you can even use e2fsadm to grow the LV and ext2 filesystem without
unmounting it.

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert