---
features:
  - Adds support to configure the size of the native thread pool used by the
    cinder volume and backup services.  For the backup we use
    `backup_native_threads_pool_size` in the `[DEFAULT]` section, and for the
    backends we use `backend_native_threads_pool_size` in the driver section.

fixes:
  - Fixes concurrency issue on backups, where only 20 native threads could be
    concurrently be executed.  Now default will be 60, and can be changed with
    `backup_native_threads_pool_size`.
  - RBD driver can have bottlenecks if too many slow operations are happening
    at the same time (for example many huge volume deletions), we can now use
    the `backend_native_threads_pool_size` option in the RBD driver section to
    resolve the issue.