ef43c464ee
Part of "consistency-file-rename" spec [1] This commit also changes the following: * Update corresponding references to common in various guides * Rename excluded_patterns in conf.py of various guide * Rename existing entries in www/static/.htaccess * Add entries to .htaccess to redirect renamed files [1] http://specs.openstack.org/openstack/docs-specs/specs/newton/consistency-file-rename.html Change-Id: I39a9d5b95535cad1918ee64e95dee5ef18ab2cbe
62 lines
2.4 KiB
ReStructuredText
62 lines
2.4 KiB
ReStructuredText
================
|
|
Storage concepts
|
|
================
|
|
|
|
The OpenStack stack uses the following storage types:
|
|
|
|
.. list-table:: Storage types
|
|
:header-rows: 1
|
|
:widths: 30 30 30 30
|
|
|
|
* - On-instance / ephemeral
|
|
- Block storage (cinder)
|
|
- Object Storage (swift)
|
|
- File Storage (manila)
|
|
* - Runs operating systems and provides scratch space
|
|
- Used for adding additional persistent storage to a virtual machine (VM)
|
|
- Used for storing virtual machine images and data
|
|
- Used for providing file shares to a virtual machine
|
|
* - Persists until VM is terminated
|
|
- Persists until deleted
|
|
- Persists until deleted
|
|
- Persists until deleted
|
|
* - Access associated with a VM
|
|
- Access associated with a VM
|
|
- Available from anywhere
|
|
- Access can be provided to a VM
|
|
* - Implemented as a filesystem underlying OpenStack Compute
|
|
- Mounted via OpenStack Block Storage controlled protocol (for example, iSCSI)
|
|
- REST API
|
|
- Provides Shared File System service via nfs, cifs, glusterfs, or hdfs protocol
|
|
* - Encryption is available
|
|
- Encryption is available
|
|
- Work in progress - expected for the Mitaka release
|
|
- Encryption is not available yet
|
|
* - Administrator configures size setting, based on flavors
|
|
- Sizings based on need
|
|
- Easily scalable for future growth
|
|
- Sizing based on need
|
|
* - Example: 10 GB first disk, 30 GB/core second disk
|
|
- Example: 1 TB "extra hard drive"
|
|
- Example: 10s of TBs of data set storage
|
|
- Example: 1 TB of file share
|
|
|
|
.. note::
|
|
|
|
- *You cannot use OpenStack Object Storage like a traditional hard
|
|
drive.* The Object Storage relaxes some of the constraints of a
|
|
POSIX-style file system to get other gains. You can access the
|
|
objects through an API which uses HTTP. Subsequently you don't have
|
|
to provide atomic operations (that is, relying on eventual
|
|
consistency), you can scale a storage system easily and avoid a
|
|
central point of failure.
|
|
|
|
- *The OpenStack Image service is used to manage the virtual machine
|
|
images in an OpenStack cluster, not store them.* It provides an
|
|
abstraction to different methods for storage - a bridge to the
|
|
storage, not the storage itself.
|
|
|
|
- *The OpenStack Object Storage can function on its own.* The Object
|
|
Storage (swift) product can be used independently of the Compute
|
|
(nova) product.
|