About the volumes, originally the limit on the size of volumes in DevStack was 2Gb due to the default size of the backing file created to hold the logical volumes. The default changed to 5Gb a while ago.

You can set the size of the LV backing file in locarc with VOLUMEBACKINGFILE_SIZE. To get a 10Gb max size add this to localrc:

VOLUME_BACKING_FILE_SIZE=10260M

You can verify the file size by looking at /opt/stack/data/stack-volumes-backing-file. Also the usual LVM command suspects will be helpful here (pvs, vgs, lvs, etc).

Note that if you already have a backing file, rerunning stack.sh with a new VOLUME_BACKING_FILE_SIZE WILL NOT change the existing file. You must remove it for the new size to take effect.

You can also just create a volume group named 'stack-volumes' yourself and DevStack will find it and use it instead of the backing file.

Please check quotas for tenant:

nova quota-show

If you are using mysql database, you can also check there:

use nova;
# To show usage
select * from quota_usages;
# To show quotas
select * from quotas;

I want to append a question: when I shutdown a instance ,its resource(RAM,vcpu) is also in nova resource pool rather than to use for other new instance creating . So how can I recover these resource to use again for others?