Re: [linux-lvm] LVM Volume Size Question

[ctd@minneapolish3.com]

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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@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@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@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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 read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
 

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