[linux-lvm] LVM Volume Size Question
ctd at minneapolish3.com
ctd at minneapolish3.com
Fri Jan 23 18:02:45 UTC 2009
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}Francois,
Here is the output you requested:
mythserver michael # vgdisplay -v vg
Using volume group(s) on command line
Finding volume group "vg"
--- Volume group ---
VG Name vg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 10
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 1.59 TB
PE Size 4.00 MB
Total PE 417316
Alloc PE / Size 417024 / 1.59 TB
Free PE / Size 292 / 1.14 GB
VG UUID 2a2Vzo-3HUx-gUU0-EYk3-md1s-PgAg-MM0bQ6
--- Logical volume ---
LV Name /dev/vg/myth
VG Name vg
LV UUID 4Auu9y-47vW-6BBd-Rdd5-PP63-3sYB-lvmNmQ
LV Write Access read/write
LV Status available
# open 1
LV Size 1.59 TB
Current LE 417024
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0
--- Physical volumes ---
PV Name /dev/sdc1
PV UUID DX11mo-r0Eh-jN5N-objS-oqo6-eVSU-MShkS2
PV Status allocatable
Total PE / Free PE 238466 / 0
PV Name /dev/sdb1
PV UUID SetyUA-DkWL-zDDo-W8Om-3avR-nJH8-OnUujv
PV Status allocatable
Total PE / Free PE 178850 / 292
mythserver michael # lvdisplay /dev/vg/myth
--- Logical volume ---
LV Name /dev/vg/myth
VG Name vg
LV UUID 4Auu9y-47vW-6BBd-Rdd5-PP63-3sYB-lvmNmQ
LV Write Access read/write
LV Status available
# open 1
LV Size 1.59 TB
Current LE 417024
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0
So it does appear that /dev/vg/myth is the full 1.59TB. Any reason
that it appears that the output of df does not agree with this or am I
confused?
Regarding your recommended steps, I understand that those steps will
not eliminate my reliance on the two drives not failing but the steps
will setup a stripped mapping which can improve performance, right?
In my situation, the directory mapped to /dev/vg/myth is just used
to store recorded programs from mythtv. Therefore, the data is not
critical, but the desire is to present a directory that is as big as
possible to allow mythtv to not run out of recording space (I think
1.6TB should do it!!!).
Also, I assume that the second "dd" command line you wrote should
have referenced /dev/sdc and not sdb, correct?
Thanks a ton for your insight.
Take it easy,
Mike
On Fri 09/01/23 10:44 , "F-D. Cami" fcami at winsoft.fr sent:
Hi Mike,
Could you give us the output of :
vgdisplay -v vg
lvdisplay /dev/vg/myth
I think your myth LV is already 1.5TB, so you only need to run :
# mount -o remount,resize /dev/vg/myth
for the JFS filesystem to be resized.
Please backup everything before running that :)
However, since what you're doing essentially amounts to RAID0
without the
performance benefits (if you lose one drive, your data is lost), I'd
run a full backup
and run the following commands to create a striped LV :
lvremove /dev/vg/myth
vgremove vg
pvremove /dev/sdb1
pvremove /dev/sdc1
dd if=/dev/zero of=/dev/sdb bs=4096 count=10000
dd if=/dev/zero of=/dev/sdb bs=4096 count=10000
pvcreate /dev/sdb
pvcreate /dev/sdc
vgcreate vg /dev/sdb /dev/sdc
lcreate -i 2 -I 8 -L 1700M -n myth vg /dev/sdb /dev/sdc
(adjust 1700 to whatever your drives will take)
mkfs.jfs /dev/vg/myth
You will lose a bit of space but gain some performance ; the
available VG size can
then be used for other LVs or snapshots.
Best,
Francois
On Fri, 23 Jan 2009 11:14:35 -0600
ctd at minneapolish3.com [1] wrote:
> Hey there,
>
>
>
> I have most likely a simple question concerning LVM that I figured
someone might be able to provide some insight into.
>
>
>
> I just setup LVM with both /dev/sdb1 and /dev/sdc1 being assigned
to my “vg” volume group. There is only one logical volume
“myth” off of “vg”.
>
>
>
> My steps:
>
> fdisk /dev/sdc [created 1 partition to span the entire drive of
type 8e]
> emerge lvm2
> vgscan
> vgchange -a y
> pvcreate /dev/sdc1
> vgcreate vg /dev/sdc1
> lvcreate -L900GB -nmyth vg
> mkfs.jfs /dev/vg/myth
> fdisk /dev/sdb [created 1 partition to span the entire drive of
type 8e]
> pvcreate /dev/sdb1
> vgextend vg /dev/sdb1
> lvextend -L+700G /dev/vg/myth
>
>
> Sdb1: 700GB drive with one partition
>
> Sdd1: 1TB drive with one partition
>
>
> My question is related to the space available in /dev/vg/myth. I
> would assume that I should have ~1.7TB of space on that logical
> partition, but df does not seems to indicate that.
>
>
> # df
> Filesystem 1K-blocks Used Available Use% Mounted on
> …
> /dev/mapper/vg-myth 943656628 544996248 398660380 58% /mnt/store
> …
> mythserver michael # pvdisplay /dev/sdb1
> --- Physical volume ---
> PV Name /dev/sdb1
> VG Name vg
> PV Size 698.64 GB / not usable 2.34 MB
> Allocatable yes
> PE Size (KByte) 4096
> Total PE 178850
> Free PE 292
> Allocated PE 178558
> PV UUID SetyUA-DkWL-zDDo-Wm-3avR-nJH8-OnUujv
> mythserver michael # pvdisplay /dev/sdc1
> --- Physical volume ---
> PV Name /dev/sdc1
> VG Name vg
> PV Size 931.51 GB / not usable 3.19 MB
> Allocatable yes (but full)
> PE Size (KByte) 4096
> Total PE 238466
> Free PE 0
> Allocated PE 238466
> PV UUID DX11mo-r0Eh-jN5N-objS-oqo6-eVSU-MShkS2
> mythserver michael # lvextend -L+700G /dev/vg/myth
> Extending logical volume myth to 2.27 TB
> Insufficient free space: 179200 extents needed, but only 292
available
>
> I am guessing that I should have run these commands to extend the
logical volume to its desired size:
> vgextend vg /dev/sdb1
> lvextend -L+700G /dev/vg/myth
>
> before creating the filesystem with this command which I am
guessing locked the size to the 900GB with I used in my setup steps
> mkfs.jfs /dev/vg/myth
>
>
> Does that sound like my issue?
>
> Any thoughts on how to get out of this situation while ensuring no
loss of my data that currently resides on /dev/mapper/vg-myth?
>
>
> I am thinking that the following steps should work:
> Copy all of my files on /dev/mapper/vg-myth to other paritions (I
> assume the call to mkfs.jfs below will delete all the contents of
this
> partition)
> "lvreduce -L-641G /dev/vg/myth" (to get the size matched up with
931GB + 698GB [ 2.27TB – 931GB – 698GB)
> "mkfs.jfs /dev/vg/myth" (recreate the filesystem now that the size
has been corrected)
> remount /dev/vg/myth
> copy back the files
>
> Thanks in advance
> Mike
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at redhat.com [2]
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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Links:
------
[1] mailto:ctd at minneapolish3.com
[2] mailto:linux-lvm at redhat.com
[3] mailto:linux-lvm at redhat.com
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