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On 01/20/2017 04:07 AM, Marco Marino wrote:
> Hi, I'm trying to use cinder with lvm thin provisioning. It works well and I'd
> like to know if there is some reason lvm thin should be avoided in mitaka
> release. I'm trying to use with
> max_over_subscription_ratio = 1.0
> so I don't have problems with over subscription.
> I using thin provisioning because it is fast (I think). More precisely, my use
> case is:
>
> - create one bootable volume. This is a long operation because cinder download
> the image from glance, qemu-img convert in raw format and then "dd" copy the
> image in the volume.
> - Create a snapshot of the bootable volume. Really fast and reliable because the
> original volume is not used by any vm.
> - Create a new volume from the snapshot. This is faster than create a new
> bootable volume.
>
> Is this use correct? Can I deploy in the production environment (mitaka - centos 7)
> Thank you

For what it's worth we're using cinder with LVM thin provisioning in production 
with no overprovisioning.

What you're proposing should work, you're basically caching the vanilla image as 
a cinder snapshot.

If you wish to speed up volume deletion, you can set "volume_clear=none" in the 
cinder.conf file.

Be aware that LVM thin provisioning will see a performance penalty the first 
time you write to a given disk block in a volume, because it needs to allocate a 
new block, zero it out, then write the new data to it.

Chris