[linux-lvm] Beginner Questions

[pham_cuong at emc.com]

When you format, unless you specify the block size, the default block
size is used.
The default block size is defined based on the size of the logical disk
(partition) size that you've created.
Any disk space left over from the format is listed as unusable (for the
block size that's being used) can not be used because it's not a
multiple of the block size used to format that logical drive/partition.
 
The only way that you can make use of the remaining very small disk
space is to use the smaller block size when formatting.   However,
unless you know exactly what you're doing, it's not advisable for you to
do so since this will more likely impact the performance of your logical
drive/partition.  A lot of testing were done to determine the optimal
block size based on the size of the logical drive/partition that you've
created.
 
Except for academic reason(s), you should not be concerned with such a
small left over.
 
Regards,
 

________________________________

From: linux-lvm-bounces at redhat.com [mailto:linux-lvm-bounces at redhat.com]
On Behalf Of Joseph L. Casale
Sent: Monday, November 12, 2007 4:34 PM
To: 'linux-lvm at redhat.com'
Subject: [linux-lvm] Beginner Questions



Hi,
I have Fedora Core 7 with  LVM version: 2.02.24 (2007-03-19), Library
version: 1.02.17 (2007-01-29) and  Driver version: 4.11.0 setup.

I have two hardware raid cards each with one array partitioned fully at
799.9GB and 1499.9GB. When I try run to pvcreate /dev/sdb1 /dev/sdc1 it
creates the pvs and when I run pvdisplay I get this:

 

  --- Physical volume ---

  PV Name               /dev/sdb1

  VG Name               name

  PV Size               745.00 GB / not usable 3.67 MB

  Allocatable           yes

  PE Size (KByte)       4096

  Total PE              190718

  Free PE               190718

  Allocated PE          0

  PV UUID               yQyVCe-tiS4-Ma1E-hilJ-niuG-KXL9-jkKVIk

 

  --- Physical volume ---

  PV Name               /dev/sdc1

  VG Name               name

  PV Size               1024.00 GB / not usable 8192.00 EB

  Allocatable           yes

  PE Size (KByte)       4096

  Total PE              357626

  Free PE               357626

  Allocated PE          0

  PV UUID               PURHhY-Lo1T-5bif-HjGP-dP3o-NVTs-71ZKUm

 

Why is some space "not usable"?

 

Thanks!
jlc

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