[SOLVED] LVM little problem

HuMan-BiEnG · 07-18-2014, 12:07 AM

Hello there,
i'm preparing for RHCSA exam
but i have a problem when implementing this lvm :

Code:

Create the LV of size 50 Physical  Extent value by creating vg of size 16MB & mount it on /mnt/data2 directory

where solution for this lvm are :

Code:

Create a new partition of size 805 M and convert it to LVM
pvcreate /dev/vda6
vgcreate –s 16M <VG NAME> /dev/vda6
lvcreate –L 800M –n <LV NAME> <VGNAME>
 mkfs.ext4 <LVM PATH>
mkdir /mnt/data2
vim /etc/fstab
- add : 
<LV PATH>          /mnt/data2        FS           defaults               1 2
mount –a

now my question is why creating a partition of size 805 M ? from where the size 805 M come from ?
any help will be appreciated

HuMan-BiEnG · 07-18-2014, 09:35 AM

Hello there,
any updates for this problem ??

rknichols · 07-18-2014, 09:38 AM

The LV itself is 800MB (50 extents of 16MB each). The extra 5MB is space for the PV header and metadata.

T3RM1NVT0R · 07-18-2014, 09:54 AM

For questions related to disk partitioning Red Hat consider +/- 10 MB. Also if you check the vgdisplay output on your system it will show as 16 GiB not 16 GB. There is difference between GiB and GB. Let me put it this way:

1000 MB = 1 GB (Gigabyte)
1024MB = 1 GiB (Gibibyte)

That is where the difference is coming from. I hope this helps.

HuMan-BiEnG · 07-18-2014, 11:18 AM

Quote:

Originally Posted by rknichols

The LV itself is 800MB (50 extents of 16MB each). The extra 5MB is space for the PV header and metadata.

Hello rknichols,
thank you so much man

this really was a very big problem for me but because your appreciated help i get understand now,
thank you again
please accept my best regards,,

HuMan-BiEnG · 07-18-2014, 11:21 AM

Quote:

Originally Posted by T3RM1NVT0R

For questions related to disk partitioning Red Hat consider +/- 10 MB. Also if you check the vgdisplay output on your system it will show as 16 GiB not 16 GB. There is difference between GiB and GB. Let me put it this way:

1000 MB = 1 GB (Gigabyte)
1024MB = 1 GiB (Gibibyte)

That is where the difference is coming from. I hope this helps.

Hello T3RM1NVT0R,
thanks man so much for this important notice that i have never known before

but because of you i have notice this & i will make use of it
please accept my best regards,,

T3RM1NVT0R · 07-18-2014, 11:24 AM

you're welcome!