Really thank you!! It's difficult for me find help on cinder and I think this is the right place! @Duncan, if my goal is to speeding up bootable volume creation, I can avoid to use thin provisioning. I can use image cache and in this way the "retrieve from glance" and the "qemu-img convert to RAW" parts will be skipped. Is this correct? And whit this method I don't have a performancy penalty mentioned by Chris. @Chris: Yes, I'm using volume_clear option and volume deletion is very fast
Marco 2017-01-20 18:24 GMT+01:00 Duncan Thomas <duncan.tho...@gmail.com>: > There's also cinder functionality called the 'generic image cache' that > does this for you; see the (per-backend) config options: > image_volume_cache_enabled, image_volume_cache_max_size_gb and > image_volume_cache_max_count > > On 20 January 2017 at 16:54, Chris Friesen <chris.frie...@windriver.com> > wrote: > >> 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 >> >> >> ____________________________________________________________ >> ______________ >> OpenStack Development Mailing List (not for usage questions) >> Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscrib >> e >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> > > > > -- > -- > Duncan Thomas > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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