[rhn-users] LVM

Sead Dzelil (Student) sead.dzelil at wku.edu
Tue Jun 27 22:45:46 UTC 2006


I did the fdisk step and rebooted OK. When I run pvdisplay I get the 
following though: 

[root at ip023-8 ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda5
  VG Name               VolGroup00
  PV Size               66.06 GB / not usable 0
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              2114
  Free PE               2
  Allocated PE          2112
  PV UUID               akfgOT-b3oe-juDZ-0QGR-Y5Be-RezY-xjIZ8k

When I run vgdisplay I get this:

[root at ip023-8 ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               66.06 GB
  PE Size               32.00 MB
  Total PE              2114
  Alloc PE / Size       2112 / 66.00 GB
  Free  PE / Size       2 / 64.00 MB
  VG UUID               x6mvEM-VYuO-muql-HqN7-jrTz-lr3n-a6d8k6

Notice the Free PE? What should I do?

Sead





On Mon, 26 Jun 2006 19:08:04 -0400
 Greg Forte <gforte at leopard.us.udel.edu> wrote:
> OK.  First, you need to extend the partition.
> 
> run fdisk, delete both the linux LVM partition (sda5) and the 
extended partition (sda4) - scary, huh?  ;-)  Then recreate them, 
first the extended, starting at cylinder 284 and filling the available 
space (out to 17816).  Then recreate sda5, also starting at 284 and 
filling the available space.  Make sure you get the types set 
correctly (fdisk should set sda4's automatically to 5, but you'll have 
to set sda5's to 8e manually).  triple check everything before you 
commit changes - at least you can quit without committing if there's 
any doubt.
> 
> Assuming that works and nothing's toasted yet (you might want to 
reboot just to verify that it's not busted), run pvdisplay again and 
it should say something like 4400 Total PE, 2112 still allocated, 
whatever the difference is Free.  If so, run vgdisplay and it should 
similarly show a bunch more Free PE.  Run this:
> 
> lvextend -t -l +## /dev/VolGroup00/LogVol00
> 
> that's a lowercase L for the -l option, not a 1, and replace ## with 
the 
> value that was shown on the left for "Free PE" when you ran 
vgdisplay.
> -t tells it to test - it won't actually make the change.  Assuming
> everything's right, you should get something like:
> 
>      Test mode: Metadata will NOT be updated.
>      Extending logical volume LogVol00 to 144.00 GB
>      Logical volume LogVol00 successfully resized
> 
> Obviously, the size shown will probably be different.  If you see 
that
> then re-run the lvextend command above without the -t option, and 
you'll
> have extended the volume.
> 
> Now all you need to do is expand the filesystem:
> 
> resize2fs -p /dev/VolGroup00/LogVol00
> 
> note that you aren't specifying a size; resize2fs will automatically
> detect the size of the "partititon" (logical volume) and grow the
> filesystem to fill it.  There's no test mode for resize2fs, but it's
> pretty foolproof.  The -p option just makes it display a progress 
bar.
> 
> And that should be it!  If that all worked, 'df' should now show your
> newly grown disk.
> 
> If not, you'll have to start over from scratch, I'm afraid.
> 
> In retrospect, an easier way to fix this would've been to simply 
split the RAID1 mirror, boot from one of the disks, then extend the 
volume group to the second disk and then extend the logical volume as 
described above.  But you'd already run the conversion, I guess.  You 
could try converting it back and doing that instead, but that'll take 
forever - the process described above should only take a few minutes - 
assuming it doesn't blow everything away.  ;-)
> 
> Good luck, again!
> 
> -g
> 
> 
> Sead Dzelil (Student) wrote:
> > OK. Here is the output of these commands:
> > 
> > [root at ip023-8 ~]# fdisk -l
> > 
> > Disk /dev/sda: 146.5 GB, 146548981760 bytes
> > 255 heads, 63 sectors/track, 17816 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> > 
> >    Device Boot      Start         End      Blocks   Id  System
> > /dev/sda1               1           9       72261   de  Dell 
Utility
> > /dev/sda2   *          10         270     2096482+   6  FAT16
> > /dev/sda3             271         283      104422+  83  Linux
> > /dev/sda4             284        8908    69280312+   5  Extended
> > /dev/sda5             284        8908    69280281   8e  Linux LVM
> > 
> > [root at ip023-8 ~]# pvscan
> >   /dev/cdrom: open failed: No medium found
> >   PV /dev/sda5   VG VolGroup00   lvm2 [66.06 GB / 64.00 MB free]
> >   Total: 1 [66.06 GB] / in use: 1 [66.06 GB] / in no VG: 0 [0   ]
> > 
> > [root at ip023-8 ~]# pvdisplay
> >   --- Physical volume ---
> >   PV Name               /dev/sda5
> >   VG Name               VolGroup00
> >   PV Size               66.06 GB / not usable 0
> >   Allocatable           yes
> >   PE Size (KByte)       32768
> >   Total PE              2114
> >   Free PE               2
> >   Allocated PE          2112
> >   PV UUID               akfgOT-b3oe-juDZ-0QGR-Y5Be-RezY-xjIZ8k
> > 
> > [root at ip023-8 ~]# lvdisplay
> >   --- Logical volume ---
> >   LV Name                /dev/VolGroup00/LogVol00
> >   VG Name                VolGroup00
> >   LV UUID                gBNQtN-YtVB-6cTR-nnYs-ayxt-9Xwo-qpKVNy
> >   LV Write Access        read/write
> >   LV Status              available
> >   # open                 1
> >   LV Size                64.06 GB
> >   Current LE             2050
> >   Segments               1
> >   Allocation             inherit
> >   Read ahead sectors     0
> >   Block device           253:0
> > 
> >   --- Logical volume ---
> >   LV Name                /dev/VolGroup00/LogVol01
> >   VG Name                VolGroup00
> >   LV UUID                Pnep7s-BlfT-VUED-9dHi-0yH9-z1Wa-59cM0L
> >   LV Write Access        read/write
> >   LV Status              available
> >   # open                 1
> >   LV Size                1.94 GB
> >   Current LE             62
> >   Segments               1
> >   Allocation             inherit
> >   Read ahead sectors     0
> >   Block device           253:1
> > 
> > [root at ip023-8 ~]# vgdisplay
> >   --- Volume group ---
> >   VG Name               VolGroup00
> >   System ID
> >   Format                lvm2
> >   Metadata Areas        1
> >   Metadata Sequence No  3
> >   VG Access             read/write
> >   VG Status             resizable
> >   MAX LV                0
> >   Cur LV                2
> >   Open LV               2
> >   Max PV                0
> >   Cur PV                1
> >   Act PV                1
> >   VG Size               66.06 GB
> >   PE Size               32.00 MB
> >   Total PE              2114
> >   Alloc PE / Size       2112 / 66.00 GB
> >   Free  PE / Size       2 / 64.00 MB
> >   VG UUID               x6mvEM-VYuO-muql-HqN7-jrTz-lr3n-a6d8k6
> > 
> > I hope you guys can help. Thanks in advance!
> > 
> > Sead
> > 
> > 
> > 
> > 
> > On Mon, 26 Jun 2006 18:29:18 -0400
> >  "Lamon, Frank III" <Frank_LaMon at csx.com> wrote:
> >> Lots of red flags all over the place here - converting a mirrored 
set
> > to a striped set on the fly sort of (it sounds like you haven't 
reloaded
> > the OS)? 
> >> But let's see what you have now. Can you give us the output of the
> > following commands?
> >> fdisk -l
> >> pvscan
> >> pvdisplay
> >> lvdisplay
> >> vgdisplay
> >>
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: rhn-users-bounces at redhat.com
> >> [mailto:rhn-users-bounces at redhat.com]On Behalf Of Sead Dzelil 
(Student)
> >> Sent: Monday, June 26, 2006 6:16 PM
> >> To: gforte at udel.edu; Red Hat Network Users List
> >> Subject: Re: [rhn-users] LVM
> >>
> >>
> >> Thank you very much for taking the time to help me. I only have 
two 73GB
> >> hard drives right now and I need 100+GB of storage. I am not 
concerned
> >> about redundancy because the server is used for computations, not 
for
> >> important storage. Please help me out if you know your LVM. The 
computer
> >> sees the whole 146GB but the volume group is on only 73GB. What 
can I
> >> too to resize it and make the OS see the whole disk. Please help.
> >>
> >> Thank You
> >>
> >> On Mon, 26 Jun 2006 04:58:19 -0400
> >>  Greg Forte <gforte at leopard.us.udel.edu> wrote:
> >>> Wow, where to start ...
> >>>
> >>> First of all, Travers: he's already got hardware raid, he said as
> >> much: "... went into the RAID BIOS ...".  It's built-in to the 
6800
> > series.
> >>> Sead: your foremost problem is that you don't have enough disk 
space
> >> for any kind of meaningful redundancy if you need 100+ GB.  RAID0 
isn't
> >> really RAID at all (unless you replace "redundant" with "risky") -
 RAID0
> >> stripes the data across N of N disks with no parity data, which 
means if
> >> one disk fails the whole system is gone.  Instantly.  It's 
basically
> >> JBOD with a performance boost due to multiplexing reads and 
writes.  To
> >> put it bluntly, no one in their right mind runs the OS off of a 
RAID0
> >> volume.
> >>> Beyond that, I'm surprised (impressed?) that the OS even still 
boots -
> >> after the conversion any data on the disks should be scrap.  
Maybe the
> >> newer Dell RAID controllers are able to convert non-
destructively.  I'll
> >> assume that's true, in which case the reason the OS doesn't see 
the
> >> difference is because you still need to change both the partition 
size
> >> (in this case, the logical volume extent size) and the filesystem
> >> itself.  In which case you COULD theoretically use lvextend to 
enlarge
> >> the LVM volume, and then resize2fs to grow the filesystem 
(assuming it's
> >> ext2/3, which it almost definitely is).  BUT, there's still the 
problem
> >> I mentioned above.
> >>> The first thing you need to do is fix the physical disk problem.
> >> Depending on how the machine is configured, this may be easy or 
hard.
> >>> A 6800 has 10 drive slots on the main storage backplane (the 
bays on
> >> the right), and if the two existing drives are on that backplane 
then it
> >> _should_ be a simple matter of buying a third 73GB disk, 
installing it,
> >> going into the RAID BIOS and converting again to RAID5 (assuming 
it can
> >> also do that conversion without trashing the disks - I'm guessing 
it can
> >> if it did RAID1 to RAID0), and then doing lvextend and resize2fs 
as
> >> described above (I know, you want more detail, but you need the 
disk
> >> first ;-)
> >>> BUT ... I'm gonna go out on a limb and guess that the machine was
> >> configured with the 1x2 secondary backplane in the peripheral bay 
area
> >> on the left.  If that's the case, then you're not going to be 
able to
> >> add a third disk in that area, and I don't think you can 
configure a
> >> raid with disk members on different backplanes - and even if you 
can,
> >> I'd guess the 10 bays in the main storage are all filled, or it 
wouldn't
> >> be configured with the extra backplane to begin with.  You'd have 
to
> >> check with Dell tech support about that, to be sure.  But 
assuming all
> >> of my guesses are right, the only option left is going to be to 
buy two
> >> larger disks and configure them for RAID1, just like the two 73's 
you've
> >> got now.  The other bad news in that situation is that you're 
probably
> >> going to have to reinstall from scratch - you could probably 
manage to
> >> image from the existing volume to the new one, but it's also 
almost
> >> surely going to end up being more effort (if you've never done 
that sort
> >> of thing
> >>> before) than simply re-installing.
> >>>
> >>> Good luck!  Once you do get the disk situation worked out, let 
us know
> >> and I (or someone else) can help you through the 
lvextend+resize2fs, if
> >> necessary.  I suspect you won't end up needing that, though.
> >>> -g
> >>>
> >>> Travers Hogan wrote:
> >>>> It looks as if you have software raid 1. You cannot change this-
you
> >> must rebuild your system. I would also suggest getting a hardware 
raid
> >> controller.
> >>>> rgds
> >>>> Trav
> >>>>
> >>>> ________________________________
> >>>>
> >>>> From: rhn-users-bounces at redhat.com on behalf of Sead Dzelil 
(Student)
> >>>> Sent: Sun 25/06/2006 03:10
> >>>> To: rhn-users at redhat.com
> >>>> Subject: [rhn-users] LVM
> >>>>
> >>>>
> >>>>
> >>>> I am a system administrator with no experience with lvm. I have 
used
> >>>> fdisk in the past and I was very comfortable with that. I have 
a very
> >>>> important question. I have a Dell PowerEdge 6800 server that 
came with
> >>>> two 73GB hard drives in a RAID 1 configuration. The order was 
placed
> >>>> wrongly, because we need 100+ GB of storage. I went into the 
RAID BIOS
> >>>> and changed it from RAID 1 to RAID 0. Now the RAID BIOS display 
the
> >>>> logical volume with the full 146GB of storage.
> >>>>
> >>>> The problem is that in the OS(RedHat Enterprise) nothing has 
changed.
> >>>> It still only sees the 73GB of storage. What can I do to get the
> >>>> system to see the whole 146GB? I need as detail info as possible
> >>>> because I have never used lvm before. Thank You in advance.
> >>>>
> >>>> Sead
> >>>>
> >>>> _______________________________________________
> >>>> rhn-users mailing list
> >>>> rhn-users at redhat.com
> >>>> https://www.redhat.com/mailman/listinfo/rhn-users
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> > -------------------------------------------------------------------
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