Logical Volume Important question

splinux · 06-30-2011, 08:49 AM

When we install the OS, we can create the volume group ?

if we select the default layout, the system creating volume group automatically. so we cant create in OS installation time ?

acid_kewpie · 06-30-2011, 09:01 AM

You've not even said what distro you're talking about, but if you mean RHEL / CentOS then you are free to choose if you don't choose default layout.

I don't understand how you expect to be able to create volume groups when you are selecting "default layout"? Kind of defeats the point of it doesn't it??

splinux · 06-30-2011, 09:04 AM

i am using centos 5.6.

acid_kewpie · 06-30-2011, 09:05 AM

right, so my previous answer applies.

splinux · 06-30-2011, 09:09 AM

This is my target.

I have install the centos then i have create virtualization

Base OS 5.6

i have to create two virtualizal OS 5.6
One is for mail server
another one is for web server

but any tiem i should able to extend space when i require for mail server or web server.

plz tell me good solution for this

acid_kewpie · 06-30-2011, 09:11 AM

a solution for what?? You want to be able to add more space to an LV in the future? the disk management tools can handle this, but it's pretty simple to do manually. Plenty of guides available. There's no consequence of your method of installation if it's already LVM.

splinux · 06-30-2011, 09:14 AM

if use the tools then not loosing any data ?

acid_kewpie · 06-30-2011, 09:18 AM

extending an LVM volume is not at all dangerous.

Extending the filesystem that is on the volume can be dangerous though. You should be aware of the layers involved here...

- Disk
- LVM type Partition
- Physical volume
- Volume Group
- Logical Volume
- Filesystem
- Files

whilst the size of the LV should be the same size as the filesystem they are VERY different things. That said using a tool like resize2fs is very simple and generally very benign when englarging it.

splinux · 06-30-2011, 09:28 AM

i am very new in linux thats why i asked. i will get the back up every time.
i dont have any experience in such tools can u send me name of the link that tool ?
if i want to use that tool , i have install in which file system ?
LVM or normal file system

acid_kewpie · 06-30-2011, 09:34 AM

it doesn't matter when you install it. I would strongly suggest planning properly in the first place. Make sure you don't need to make changes and you'll be much better off.