On Sat, 2006-12-23 at 15:04 -0500, Kamaraju Kusumanchi wrote: > On Friday 22 December 2006 17:09, Kamaraju Kusumanchi wrote: > > I heard lvm can be used to have partitions whose sizes can be changed over > > time in non-destructive way as far as the data is concerned. > > > > Another basic question regarding the use of lvm. If I have traditionally > partitioned harddrive running debian Etch, can I make those partitions use > lvm without loosing any data? I have been reading the HOWTO at > http://www.tldp.org/HOWTO/LVM-HOWTO/ and it does not mention whether all > these commands vgcreate etc., work destructively or non-destructively. > > Any ideas?
Better have backups. The answer is DESTRUCTIVELY. pvcreate causes the
Physical Volume to be "made ready for LVM' which means... wipeout
anything there and clear it for use.
vgcreate just put the pv you just created into a volume group. lvcreate
then carves out logical volumes for you to use as filesystems or the
like.
Examples:
princess:~# pvdisplay
--- Physical volume ---
PV Name /dev/sda1
VG Name miscVG
PV Size 279.47 GB / not usable 0
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 71545
Free PE 0
Allocated PE 71545
PV UUID fpBbEs-ZWAk-mfFQ-5fo2-HXzG-RUZ1-f3x1QE
--- Physical volume ---
PV Name /dev/sdb1
VG Name miscVG
PV Size 279.47 GB / not usable 0
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 71545
Free PE 0
Allocated PE 71545
PV UUID HqnFyL-scsV-8s6h-aaE3-KFMH-5J20-mEcK7Q
--- Physical volume ---
PV Name /dev/hdh1
VG Name miscVG
PV Size 189.91 GB / not usable 0
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 48618
Free PE 0
Allocated PE 48618
PV UUID sKP0S0-tJpj-okFQ-Zuo3-Deu5-rIkB-ppm0px
princess:~# vgdisplay
--- Volume group ---
VG Name miscVG
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 748.86 GB
PE Size 4.00 MB
Total PE 191708
Alloc PE / Size 191708 / 748.86 GB
Free PE / Size 0 / 0
VG UUID D2mpF3-G9Ax-Awb0-hr8L-w23Q-P2Ta-Qbimm9
princess:~# lvdisplay
--- Logical volume ---
LV Name /dev/miscVG/usrlocalLV
VG Name miscVG
LV UUID K7a0Dk-N5kp-NRP6-t0SW-lpuZ-k3AS-pSHSKp
LV Write Access read/write
LV Status available
# open 1
LV Size 748.86 GB
Current LE 191708
Segments 3
Allocation inherit
Read ahead sectors 0
Block device 254:0
princess:~# df /usr/local
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/miscVG-usrlocalLV
785104896 288249284 496855612 37% /usr/local
Hope that helps.
--
greg, [EMAIL PROTECTED]
The technology that is
Stronger, better, faster: Linux
signature.asc
Description: This is a digitally signed message part
