image conversion in Liberty

asked 2016-10-16 04:17:59 -0600

Bipin gravatar image

updated 2016-10-16 04:18:45 -0600

In an production setup i have noticed that, while image being copied into image cache, the file is converted to a RAW format. The Actual image is QCOW2. The following is the setup.

Mirantis Openstack Liberty, Backed by NetAPP. boot-from-image-create-volume is the boot scenario. I believe its Cinder job to doing the conversion. Question is why this conversion to RAW format, is there a specific reason for this ?


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Once I read somewhere that this happens because the raw image can be transformed faster than QCOW2 images and also they are a better fit for hypervisors

fifi gravatar imagefifi ( 2016-10-16 11:44:07 -0600 )edit

OK, Thanks. But I couldnt find a document for this.

Bipin gravatar imageBipin ( 2016-10-18 04:18:52 -0600 )edit

Do I understand you right - you boot from an image that you then attach to the instance as a volume? My guess is that Cinder volumes can't be in qcow2 format, as not all hypervisors may be be able to attach a qcow2 file to a VM.

Bernd Bausch gravatar imageBernd Bausch ( 2016-10-20 19:46:41 -0600 )edit

Perhaps it's specific to the Netapp driver, as indicated in this forum post:

Bernd Bausch gravatar imageBernd Bausch ( 2016-10-20 19:49:57 -0600 )edit