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On 10/19/2014 09:33 AM, Avishay Traeger wrote:
> Hi Preston,
> Replies to some of your cinder-related questions:
> 1. Creating a snapshot isn't usually an I/O intensive operation.  Are
> you seeing I/O spike or CPU?  If you're seeing CPU load, I've seen the
> CPU usage of cinder-api spike sometimes - not sure why.
> 2. The 'dd' processes that you see are Cinder wiping the volumes during
> deletion.  You can either disable this in cinder.conf, or you can use a
> relatively new option to manage the bandwidth used for this.
>
> IMHO, deployments should be optimized to not do very long/intensive
> management operations - for example, use backends with efficient
> snapshots, use CoW operations wherever possible rather than copying full
> volumes/images, disabling wipe on delete, etc.

In a public-cloud environment I don't think it's reasonable to disable 
wipe-on-delete.

Arguably it would be better to use encryption instead of wipe-on-delete. 
  When done with the backing store, just throw away the key and it'll be 
secure enough for most purposes.

Chris