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BETA : Thin LVM in Virtualizor (Oversell KVM and Xen Disk Space)
virtualizor
Member
Hi,
We are looking for users to help us test Thin LVM support in Virtualizor.
This has been there in Virtualizor since 5 versions and was under private beta i.e. only select users were invited to test this.
We are now opening it up for the public.
Benefits :
With Thin LVM you can oversell disk space on KVM and Xen virtualized Nodes.
Guide (Do this on a new server only) :
1) Create the Thin LV :
root> lvcreate --size 100G --type thin-pool --thinpool thin_pool VolumeGroupName
2) Update the variable $globals['thin_lv'] in /usr/local/virtualizor/universal.php :
$globals['thin_lv'] = 'thin_pool';
That is it.
WARNING :
1) Thin LVM requires experienced admins to manage it
2) This feature is in BETA.
3) If your thin LV gets full all your VMs will hang.
4) If your thin LV Meta Data is lost, all your data can be lost.
5) Dont use in Production environments yet.
Licenses :
If you need licenses, email us and we will give you the licenses.
More Beta :
Many other hidden features exist in Virtualizor. Stay tuned for more beta features coming out.
Regards,
Virtualizor Team
Comments
Interesting, may have to try this on a dev box.
Now I am curious...
Any news on IP Pools being able to be assigned to certain plans. e.g. internal range for package1 and external for package2?
No Idea, certain things only the devs know
But please elaborate your requirement and I will forward it to the devs.
PM'd.
So, no more "not overselling" kvm and xen ?
Yes, if you set it up with Thin LVM. But thin lvm should be used by experienced admins or please research on it first and then take the plunge.
Thin provisining is nothing new
Back to 2008 when I used VMware to create virtual machine, the size of VM's image is the actual size of data inside it.
It isnt new, but most providers dont have this feature as many panels dont support it yet.
Then I'm sure I will stay away from KVM or XEN providers use Virtualizor. Because in my mind KVM and XEN resource should be dedicated.
@wych well it depends. If there is a way to check it's enabled or not, then it should be fine. Otherwise I will stay away from something I can't check.
And they are if you use a provider that hasn't enabled Thin Provisioning...
Thats like saying I wont use xyz software as it can be configured in this way, although other configs exist.
Most cloud providers have Thin Provisioning. Thin provisioning isnt that bad. If you have Hardware Raid and use Thin provisioning you still would have pretty good IO.
@virtualizor
Can I grab a licence to check you guys out, please?
Sure, just email us the IP of your new server.
What's your email?
Just PM me for now.
How do you handle the reclaimation of blocks when the data is written once? I've seen a lot of major platforms having no good way for reclaimation (Starwinds, Nexenta, etc.). Even VMware requires you to shut down for it and plan a maintenance window, unless I am mistaken. These are big platforms and the people using them mostly understand that risk.
If you were to release the same thing to this market, we will soon be seeing a lot more downtime threads for cheap KVM/Xen providers who do not understand how it works, nobody will care about the "experienced admins" requirement.
Did you happen to remove some files inside the VM and check the disk usage on the VMware side? Because it will show you that it has decreased inside the VM, but in VMware, it will just count "writes" and keep using more space on your datastore, until it's full.
@Abdullah You're right, the image just bigger and bigger when there are more data, when I delete data, its size doesn't change.
@virtualizor it's good or not based on how people use it. If it can be oversold, we will soon see G*VM provide cheap KVM/XEN and cheat people.
@Abdullah the feature would be there in Virtualizor. Its the admins call to use it or not. Also about VMware, it mainly uses vmdk format. Vmdk has a shrink file feature which will reduce used deleted space inside a VM.
Oh dear god... I give it 3 days before some high profile failure.
This is not something new. However, as a customer if you are afraid a provider is doing this in KVM, simply use an encrypted file system and be sure to do a full 'erase' during install. This will cause all of the space to be allocated that your allowed to have and will prevent that space not being available at any point in the future. This 'feature' only works for those who choose to use a default template and never allocate their full space.
If you are a provider and have to resort to thin provisioning.... you probably shouldn't be in this business. However, there are applications in a business environment for this. If you were in a business situation where you needed to run several vms and you weren't 100% sure how much space you were going to need on a per vm basis, at least this would allow you to allocate space as needed.
Cheers!
Development is going the way providers want it to go: main feature Thin LVM. No matter how you put it, it's called cheating and most providers will use the feature.
I will stay away from hosts using virtualizor, though I am sure many other providers, that have people with experience and knowledge and are not 'Sunday admins' are already using different 'features' to do the same thing, the only change will be that now all the '2 week' admins will use it also filling the market with 100-200GB SSD offers at $1.
We were requested to make this and we have done what our customers asked for.
I would again say that thin provisioning isnt that bad and in certain situations like deploying a Cloud where you have expensive hardware and SAN storage with various RAID combinations, its a plus to have thin provisioning. Many cloud providers who have SSD offerings do thin provisioning.
I'm relatively sure SolusVM has had this feature for a long time. But I could be wrong, so don't take my word for it
As far as I know they dont support thin LVM.
Not officially. Unofficially, there's always been ways to get it done.
Why on earth does it even matter?
Petulance.
Urgh! Wrong thread.
I guess the car is out of the bag. Lol