Increase CephFS backing file size

The backing file constitutes to the disk space
on the fake OSDs created.

In an effort to fix bug #1890833 we realized
that more space is needed to run manila tempest
tests at a high concurrency.

Change-Id: Ic96b65d2caab788afca8bfc45575f3c05dc88008
Signed-off-by: Goutham Pacha Ravi <gouthampravi@gmail.com>
diff --git a/zuul.d/manila-tempest-jobs.yaml b/zuul.d/manila-tempest-jobs.yaml
index cb7c080..ebb86f2 100644
--- a/zuul.d/manila-tempest-jobs.yaml
+++ b/zuul.d/manila-tempest-jobs.yaml
@@ -295,6 +295,7 @@
         devstack-plugin-ceph: https://opendev.org/openstack/devstack-plugin-ceph
       tempest_test_regex: manila_tempest_tests.tests
       devstack_localrc:
+        VOLUME_BACKING_FILE_SIZE: 60GB
         SHARE_DRIVER: manila.share.drivers.cephfs.driver.CephFSDriver
         MANILA_ENABLED_BACKENDS: cephfsnative
         ENABLED_SHARE_PROTOCOLS: CEPHFS
@@ -336,6 +337,7 @@
         devstack-plugin-ceph: https://opendev.org/openstack/devstack-plugin-ceph
         neutron-dynamic-routing: https://opendev.org/openstack/neutron-dynamic-routing
       devstack_localrc:
+        VOLUME_BACKING_FILE_SIZE: 60GB
         SHARE_DRIVER: manila.share.drivers.cephfs.driver.CephFSDriver
         MANILA_ENABLED_BACKENDS: cephfsnfs
         ENABLED_SHARE_PROTOCOLS: NFS