CentOS - Feb 2011 - can't create large LVM, even though pvscan shows enough space left

I'm trying to create a 500GB lv volume on a 500GB physical volume, but
can't:

[root at francois-pc ~]# pvscan
  PV /dev/sdd                  VG freenas      lvm2 [500.00 GB / 500.00 GB free]
  PV /dev/sdc                  VG thecus       lvm2 [1010.00 GB /
910.00 GB free]
  PV /dev/mapper/ddf1_RAIDp2   VG VolGroup00   lvm2 [931.25 GB / 0    free]
  Total: 3 [2.38 TB] / in use: 3 [2.38 TB] / in no VG: 0 [0   ]
[root at francois-pc ~]# lvcreate -L 500gig -n 500G freenas
  Insufficient free extents (127999) in volume group freenas: 128000 required

Even dropping the size a bit, I get this:

[root at francois-pc ~]# lvcreate -L 500gig -n 450G freenas
  Insufficient free extents (127999) in volume group freenas: 128000 required



How do I actually create a 500GB volume?




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> I'm trying to create a 500GB lv volume on a 500GB physical volume, but
> can't:
>
> [root at francois-pc ~]# pvscan
>   PV /dev/sdd                  VG freenas      lvm2 [500.00 GB / 500.00 GB
> free]
>   PV /dev/sdc                  VG thecus       lvm2 [1010.00 GB /
> 910.00 GB free]
>   PV /dev/mapper/ddf1_RAIDp2   VG VolGroup00   lvm2 [931.25 GB / 0
> free]
>   Total: 3 [2.38 TB] / in use: 3 [2.38 TB] / in no VG: 0 [0   ]
> [root at francois-pc ~]# lvcreate -L 500gig -n 500G freenas
>   Insufficient free extents (127999) in volume group freenas: 128000
> required
>
> Even dropping the size a bit, I get this:
>
> [root at francois-pc ~]# lvcreate -L 500gig -n 450G freenas
You just named different, the size is the same. Did you mix up the -L and
-n options?

Simon

On Friday, February 25, 2011 08:15:34 am Rudi Ahlers
wrote:
> [root at francois-pc ~]# lvcreate -L 500gig -n 500G freenas
>   Insufficient free extents (127999) in volume group freenas: 128000
required
> How do I actually create a 500GB volume?
try
lvcreate -l 127999 -n 500G freenas

The default '500G' size is 12,800 extents, but you only have 12,799
extents free; which gets rounded *up* to 500G by the free space display.  And
that's a lower-case 'L' option, not an upper-case 'I'
option.

At Fri, 25 Feb 2011 15:15:34 +0200 CentOS mailing list <centos at
centos.org> wrote:
> 
> I'm trying to create a 500GB lv volume on a 500GB physical volume, but
can't:
> 
> [root at francois-pc ~]# pvscan
>   PV /dev/sdd                  VG freenas      lvm2 [500.00 GB / 500.00 GB
free]
>   PV /dev/sdc                  VG thecus       lvm2 [1010.00 GB /
> 910.00 GB free]
>   PV /dev/mapper/ddf1_RAIDp2   VG VolGroup00   lvm2 [931.25 GB / 0    free]
>   Total: 3 [2.38 TB] / in use: 3 [2.38 TB] / in no VG: 0 [0   ]
> [root at francois-pc ~]# lvcreate -L 500gig -n 500G freenas
>   Insufficient free extents (127999) in volume group freenas: 128000
required
> 
> Even dropping the size a bit, I get this:
> 
> [root at francois-pc ~]# lvcreate -L 500gig -n 450G freenas
>   Insufficient free extents (127999) in volume group freenas: 128000
required
'-n' is the *name*, -L is the size.  You are still asking for a 500G
sized volume.

Try this:

lvcreate -l 100%FREE -n volume freenas

This will create a logical volume (named volume) that uses all of the
*available* free space, which will be *slightly* less than the 500B of
the VG.
> 
> 
> 
> How do I actually create a 500GB volume?
You can't. There is one extent's worth of space used for LVM meta data.
> 
> 
> 
> 
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