[SOLVED] Where does lvm storage exist?

[dtiKev]

I've setup a transition machine to figure out how pmve works while I wait for hardware to arrive. I've been doing test migrations from esxi to get my technique ready.

The test setup was installed on a smallish 15k hard drive and then I used LVM commands from the cli following a doc in the wiki to extend it with 2 500GB 7200rpm drives.

It would appear that I wrongly assumed that all of the space gained was applied to / and with that thought in mind I was using clonezilla via ssh to backup to /opt/clones -- that caused a bit of a problem today so I'm asking how the lvm structure actually works.

Perhaps I should know but this whole /dev/mapper/xyz is new to me and my usual df -h isn't showing me what I'm looking for. In fact according to df I only have a 34GB root partition 13G of which are free. Since I will be utilizing the cli for automated backup to on/offsite NAS type stuff once I'm up and running I'd like to know how storage space is actually allocated.

Any docs or pointers?

Thanks,
dK

 

[dtiKev]

Okay... so upon further investigation it appears as if the are of the lvm that stores machines is actually hidden.

I've added another harddrive and formatted a large partition and mounted it and added it to fstab. This is, of course, all for the test system. I'm going to need a solid plan for the production systems. I assume that some percentages where originally used at install to decide how much root/swap/dev/data got...

Is this adjustable at install or do I have to tinker afterwards? My higher ups are fighting me on ZFS as we are going with SSDs so I'm not exactly sure what the best solution will be.

 

[wolfgang]

Hi,

Is this adjustable at install or do I have to tinker afterwards?

Both but easier is it at the installation.

I would recommend you do not extend your LVM because if one disk fail all your data are away.
Also, you have to modify the metadata pool if you extend the volume.

 

[dtiKev]

Hi,

Both but easier is it at the installation.

I would recommend you do not extend your LVM because if one disk fail all your data are away.
Also, you have to modify the metadata pool if you extend the volume.

Thanks for the reply... can you point me to a thread or wiki/doc to explain how to adjust this at installation? I ask becasue I just ran setup again with two 1TB 7200 mechanical disks and the only options I see are for fs type and which disks to you. I select ZFS RAID1 and the advnaced screen is sparse with nothing denoting space used for the different mapped areas.

 

[wolfgang]

If you use ZFS there is no such a setting.
ZFS does only allocate the used space for the dataset.
This means you can use for VM/CT all the remaining disk space and also use it in '/'.
It is dynamically allocated.
The only partition what are fix is the swap. This you have to edit later.

I thought you talk about lvm because

/dev/mapper/xyz

 

[dtiKev]

Thanks! You are correct, I was using LVM on the test machine. I've setup one of my production servers with zfs raid1 and see that all space is available. Thanks!