[linux-lvm] LVM Volume Size Question
ctd at minneapolish3.com
ctd at minneapolish3.com
Fri Jan 23 18:50:21 UTC 2009
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Francois,
Good to know about how to improve performance, but I soon realized
that I do not have another 536GB of free space my other HDDs to backup
before performing those steps.
With that said, I could not backup before resizing the partition. I
am happy to report, the resizing worked as planned.
Thanks again.
Mike
On Fri 09/01/23 11:18 , "F-D. Cami" fcami at winsoft.fr sent:
Mike,
df reports filesystem sizes, not block device sizes.
You now only need to backup and grow the filesystem.
Yes, what I meant was an improvement in performance at some space
cost, if all you need is space, don't do it.
And, yes, the 2nd dd should be sdc :)
Cheers
F
On Fri, 23 Jan 2009 12:02:45 -0600
wrote:
> BODY { font-family:Arial, Helvetica, sans-serif;font-size:12px;
> }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" 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
> [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
> > [2]
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> _______________________________________________
> linux-lvm mailing list
> [3]
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
>
> Links:
> ------
> [1]
> [2]
> [3]
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