Local LVM Storage

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killswitchin

New Member
Mar 17, 2024
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Hi,
I am new to proxmox and was wondering why my local-lvm is filling up when I transferred media files to a completely different drive. My scenario was, I had a windows 11 vm spun up with 8TB HDD, I connected an external SSD via usb and passed it through to the VM no problem but I noticed as I transferred the files not only was it filling up the HDD but also the local-lvm (NVMeSSD) as well. My questions are 1.Why would it put data on my local-lvm if I'm transferring files to a completely different drive? (please note all this is all default settings in proxmox from a fresh install) 2. When I was searching for resolution for my issue on how to remove files from the local-lVM all I could find was how to expand the local and not how to clean up the local-lvm. How do I locate and clear the data from the local-lvm so I don't have to do a fresh install and start over? (I was looking into this because there should be no reason for the local-lvm to be used and you can start getting IO errors if the local-lvm is full when starting the vm)
 
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"local-lvm" is the default storage where your virtual disks are stored. In case you didn't add more phsyical disks/storages the 8TB virtual disks of that Win 11 VM is probably stored on that "local-lvm" storage.
As with any other thin-provisioned storages...you will have to enable discard for that VM on the PVE node and tell the guest OS to do regular TRIMs/discards for space to be freed up again.
 
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But I don't understand why these storage's have to be "linked"? Sure, if the local-LVM wants to hold some proxmox info ok, they want to hold some data for the drives I have mounted ok but why dose it need to hold a copy of the files? In my mind the drives should be separate e.g. Proxmox has my 1TB NVMe and uses a certain % of it to hold some data and I can provision the rest of the storage however I want. The windows 11 vm has my 8TB HDD and should store the data I have transferred only on that drive. Also what if for example I have an 2TB external drive and I want to transfer files to my 8TB hdd but proxmox only has the 800gig or so form the NVMe? The space runs out and I can't transfer anymore data? the local-LVM almost feels like a cashe drive and wont auto trim it's self once the files have been passed through? I'm sorry if this sounds silly but I am having an issue with the logic behind the operation of the file storage. once again I am new and I'm sorry if this sounds dumb and i'm sure i'm just missing something that I don't fully understand.
 
"local-lvm" shouldn't grow unless you got virtual disks of your VMs/LXCs stored on it and you write to them. So my guess is still that you misconfigured your VM with a virtual disks on that "local-lvm".

Output of qm config YourVMsVMID , lvs and pvesm status would help.
 
Dunuin said:
"local-lvm" shouldn't grow unless you got virtual disks of your VMs/LXCs stored on it and you write to them. So my guess is still that you misconfigured your VM with a virtual disks on that "local-lvm".
Click to expand...
I think you are right and there is something i'm not understanding in the setup of the VM I will have to review and experiment with to undertsand the behavior of proxmox better.
Dunuin said:
Output of qm config YourVMsVMID , lvs and pvesm status would help.
Click to expand...
I would like to but I already did a fresh install as I am still learning and wanted to go over my setup again.
 
I think I might have an idea of what happen now. I put the storage of the OS on the local-lvm that then links any additional storage I setup in the OS to that local-lvm therefor when any data is stored on the VM it fills the local-lvm as well. At this point I need to understand if I have to find a away to separate the multiple storage devices so my other drives don't get stored on the local-lvm as well.
 
killswitchin said:
I put the storage of the OS on the local-lvm that then links any additional storage I setup in the OS to that local-lvm therefor when any data is stored on the VM it fills the local-lvm as well. At this point I need to understand if I have to find a away to separate the multiple storage devices so my other drives don't get stored on the local-lvm as well.
Click to expand...
Then it sounds like a mounting problem inside your guest OS. If you don't properly mount a filesystem but write stuff to the empty mountpoint, the data will end up on the virtual disk.
 
After a fresh install the issue is no longer occurring. thank you everyone for helping me understand this process and I hope this thread gives some incite to someone in the future who many face a similar issue.
 
First Comment on ANY forum in my life. New with Proxmox.
Saw this topic and been intrigued about it

I have wondered why some, right after proxmox install, just delete the local-lvm from the datacenter storage menu and issue the following on CLI:
lvremove /dev/pve/data
lvresize -l +100%FREE /dev/pve/root
resize2fs /dev/mapper/pve-root

I see what's happening. I have done it in some of my past installs. But curious why some do this and others say it's not a great idea.
Found the instructions pretty easily, but haven't gotten the "reason" explanation.
 
There are two cases:
A) people come from EXSi with with its image file bases storages and don't understand the LVM-Thin and its benefits of thin provisioned and snapshotable block devices or
B) they got dedicated disks only for storing VMs/LXCs, don't plan to store any virtual disks on the system disk and therefore want the whole space for the root filesystem to be able to use all the space for ISOs/templates/snippets.
 
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