Shawn Everett wrote:
On Sunday 14 October 2007, Michael Kress wrote:
I can mount them and work with them, no prob. Now I'd like to have my 25
files of 4GB file size each coherently mounted as one 100G drive. Is
this possible? Must be something like Raid 0.
TIA Michael

You might try something like this:
http://osdir.com/ml/linux.lvm.general/2003-10/msg00096.html

Personally I think it's a bad idea. :)

Shawn

Hi, I dont't like it either, but I have to adopt to the given facts. :-( Your proposed method seems to be yet elegant.
Anyways, I got a problem with it.

This is what I do:
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dd if=/dev/zero of=fake-disk-1.img bs=1M count=10
dd if=/dev/zero of=fake-disk-2.img bs=1M count=10
losetup /dev/loop0 fake-disk-1.img
losetup /dev/loop1 fake-disk-2.img
pvcreate /dev/loop0
pvcreate /dev/loop1
vgcreate /dev/vgtest /dev/loop0 /dev/loop1

[EMAIL PROTECTED]:/root [0] > vgs
 VG     #PV #LV #SN Attr   VSize  VFree
 vgtest   2   0   0 wz--n- 16.00M 16.00M

lvcreate --size=16M --name=lvtest /dev/vgtest
mkfs /dev/vgtest/lvtest
mkdir /mnt/lvtest
mount /dev/vgtest/lvtest /mnt/lvtest/

[EMAIL PROTECTED]:/root [0] > df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             3.0G  2.4G  617M  80% /
none                  256M     0  256M   0% /dev/shm
/dev/mapper/vgtest-lvtest
                      16M  140K   15M   1% /mnt/lvtest

umount /mnt/lvtest/
shutdown -r now
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So far so good.
After reboot I found this:

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[EMAIL PROTECTED]:/root [0] > lvs
 No volume groups found
[EMAIL PROTECTED]:/root [0] > vgs
 No volume groups found
[EMAIL PROTECTED]:/root [0] > pvs
(no output)
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So I tried to recover the 2 files: I had to 'losetup' the files again, but pvcreate hangs here:
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[EMAIL PROTECTED]:/root [0] > pvcreate /dev/loop0
Can't initialize physical volume "/dev/loop0" of volume group "vgtest" without -ff
[EMAIL PROTECTED]:/root [5] >
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So I did:
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[EMAIL PROTECTED]:/root [5] > pvcreate -ff /dev/loop0
Really INITIALIZE physical volume "/dev/loop0" of volume group "vgtest" [y/n]? y WARNING: Forcing physical volume creation on /dev/loop0 of volume group "vgtest"
 Physical volume "/dev/loop0" successfully created
[EMAIL PROTECTED]:/root [0] > pvcreate -ff /dev/loop1
 Couldn't find device with uuid 'Z4Dr2Q-CBeM-QDHP-26d2-O1GV-DgZh-C7Z6pK'.
 Couldn't find all physical volumes for volume group vgtest.
 Couldn't find device with uuid 'Z4Dr2Q-CBeM-QDHP-26d2-O1GV-DgZh-C7Z6pK'.
 Couldn't find all physical volumes for volume group vgtest.
 get_pv_from_vg_by_id: vg_read failed to read VG vgtest
 Physical volume "/dev/loop1" successfully created
[EMAIL PROTECTED]:/root [0] > vgcreate /dev/vgtest /dev/loop0 /dev/loop1
 Volume group "vgtest" successfully created
[EMAIL PROTECTED]:/root [0] > lvcreate --size=16M --name=lvtest /dev/vgtest
 Logical volume "lvtest" created
[EMAIL PROTECTED]:/root [0] > mount /dev/vgtest/lvtest /mnt/lvtest/
mount: you must specify the filesystem type
[EMAIL PROTECTED]:/root [32] > fsck /dev/vgtest/lvtest
fsck 1.35 (28-Feb-2004)
e2fsck 1.35 (28-Feb-2004)
Couldn't find ext2 superblock, trying backup blocks...
Resize inode not valid.  Recreate<y>? yes

/dev/vgtest/lvtest was not cleanly unmounted, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Free blocks count wrong for group #0 (7854, counted=7855).
Fix<y>? yes

Free blocks count wrong (15722, counted=15723).
Fix<y>? yes


/dev/vgtest/lvtest: ***** FILE SYSTEM WAS MODIFIED *****
/dev/vgtest/lvtest: 11/4096 files (0.0% non-contiguous), 661/16384 blocks
[EMAIL PROTECTED]:/root [1] > mount /dev/vgtest/lvtest /mnt/lvtest/
[EMAIL PROTECTED]:/root [0] >
-----8<-----8<-----8<-----8<-----8<-----8<-----8<-----8<-----

Ok, this works, but I can't rely on such a file system. Any idea on how I could get back the original logical volume lvtest without the indeed ugly file system check and without endangering the data contained in the lv?
TIA
Michael

--
Michael Kress, [EMAIL PROTECTED]
http://www.michael-kress.de / http://kress.net
P E N G U I N S   A R E   C O O L

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