openstack/swift
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OpenStack Storage (Swift)
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Samuel Merritt 7f636a5572 Allow smaller segments in static large objects 
The addition of range support for SLO segments (commit 25d5e68)
required the range size to be at least the SLO minimum segment size
(default 1 MiB). However, if you're doing something like assembling a
video of short clips out of a larger one, then you might not need a
full 1 MiB.

The reason for the 1 MiB restriction was to protect Swift from
resource overconsumption. It takes CPU, RAM, and internal bandwidth to
connect to an object server, so it's much cheaper to serve a 10 GiB
SLO if it has 10 MiB segments than if it has 10 B segments.

Instead of a strict limit, now we apply ratelimiting to small
segments. The threshold for "small" is configurable and defaults to 1
MiB. SLO segments may now be as small as 1 byte.

If a client makes SLOs as before, it'll still be able to download the
objects as fast as Swift can serve them. However, a SLO with a lot of
small ranges or segments will be slowed down to avoid resource
overconsumption. This is similar to how DLOs work, except that DLOs
ratelimit *every* segment, not just small ones.

UpgradeImpact

For operators: if your cluster has enabled ratelimiting for SLO, you
will want to set rate_limit_under_size to a large number prior to
upgrade. This will preserve your existing behavior of ratelimiting all
SLO segments. 5368709123 is a good value, as that's 1 greater than the
default max object size. Alternately, hold down the 9 key until you
get bored.

If your cluster has not enabled ratelimiting for SLO (the default), no
action is needed.

Change-Id: Id1ff7742308ed816038a5c44ec548afa26612b95
2015-12-09 10:09:13 -08:00
bin Merge "Improve swift-init usage statement" 2015-11-26 01:43:28 +00:00
doc Merge "Add more functional tests for reverse listings" 2015-11-26 04:40:02 +00:00
etc Allow smaller segments in static large objects 2015-12-09 10:09:13 -08:00
examples Add a user variable to templates 2013-09-17 11:46:04 +10:00
swift Allow smaller segments in static large objects 2015-12-09 10:09:13 -08:00
test Allow smaller segments in static large objects 2015-12-09 10:09:13 -08:00
.alltests Script for running unit, func and probe tests at once 2015-10-13 09:10:09 +02:00
.coveragerc Fix .coveragrc to prevent nose tests error 2015-09-21 10:06:29 +01:00
.functests Move the tests from functionalnosetests 2014-01-07 15:58:11 +08:00
.gitignore more probe test refactoring 2015-02-13 16:55:45 -08:00
.gitreview make git review easier 2015-04-01 12:41:44 -07:00
.mailmap Update .mailmap entry 2015-11-23 18:01:52 +00:00
.probetests Allow specify arguments to .probetests script 2013-12-24 01:18:19 -08:00
.unittests Fix coverage report for newer versions of coverage 2014-04-24 16:50:03 +00:00
AUTHORS authors and changelog update for 2.5.0 2015-10-02 21:28:15 -07:00
babel.cfg add pybabel setup.py commands and initial .pot 2011-01-27 00:01:24 +00:00
bandit.yaml Adding bandit for security static analysis testing in swift 2015-07-31 07:37:33 +05:30
CHANGELOG authors and changelog update for 2.5.0 2015-10-02 21:28:15 -07:00
CONTRIBUTING.md Add Swift Design Principles to CONTRIBUTING.md 2015-03-27 13:13:31 -04:00
LICENSE Convert LICENSE to use unix style line endings. 2012-12-19 12:48:27 -05:00
MANIFEST.in Add requirements files to the source distribution 2013-06-03 19:26:20 +04:00
README.md added testing notes to the contributing doc 2014-12-04 10:41:11 -05:00
requirements.txt Bump PyECLib requirement to >=1.0.7 2015-12-03 07:00:14 -07:00
setup.cfg versioned writes middleware 2015-08-07 14:11:32 -04:00
setup.py taking the global reqs that we can 2014-05-21 09:37:22 -07:00
test-requirements.txt Merge "Adding bandit for security static analysis testing in swift" 2015-08-12 20:55:16 +00:00
tox.ini py3: Add py34 test environment to tox 2015-11-20 09:00:59 +01:00

README.md

Swift

A distributed object storage system designed to scale from a single machine to thousands of servers. Swift is optimized for multi-tenancy and high concurrency. Swift is ideal for backups, web and mobile content, and any other unstructured data that can grow without bound.

Swift provides a simple, REST-based API fully documented at http://docs.openstack.org/.

Swift was originally developed as the basis for Rackspace's Cloud Files and was open-sourced in 2010 as part of the OpenStack project. It has since grown to include contributions from many companies and has spawned a thriving ecosystem of 3rd party tools. Swift's contributors are listed in the AUTHORS file.

Docs

To build documentation install sphinx (pip install sphinx), run python setup.py build_sphinx, and then browse to /doc/build/html/index.html. These docs are auto-generated after every commit and available online at http://docs.openstack.org/developer/swift/.

For Developers

The best place to get started is the "SAIO - Swift All In One". This document will walk you through setting up a development cluster of Swift in a VM. The SAIO environment is ideal for running small-scale tests against swift and trying out new features and bug fixes.

You can run unit tests with .unittests and functional tests with .functests.

If you would like to start contributing, check out these notes to help you get started.

Code Organization

  • bin/: Executable scripts that are the processes run by the deployer
  • doc/: Documentation
  • etc/: Sample config files
  • swift/: Core code
    • account/: account server
    • common/: code shared by different modules
      • middleware/: "standard", officially-supported middleware
      • ring/: code implementing Swift's ring
    • container/: container server
    • obj/: object server
    • proxy/: proxy server
  • test/: Unit and functional tests

Data Flow

Swift is a WSGI application and uses eventlet's WSGI server. After the processes are running, the entry point for new requests is the Application class in swift/proxy/server.py. From there, a controller is chosen, and the request is processed. The proxy may choose to forward the request to a back- end server. For example, the entry point for requests to the object server is the ObjectController class in swift/obj/server.py.

For Deployers

Deployer docs are also available at http://docs.openstack.org/developer/swift/. A good starting point is at http://docs.openstack.org/developer/swift/deployment_guide.html

You can run functional tests against a swift cluster with .functests. These functional tests require /etc/swift/test.conf to run. A sample config file can be found in this source tree in test/sample.conf.

For Client Apps

For client applications, official Python language bindings are provided at http://github.com/openstack/python-swiftclient.

Complete API documentation at http://docs.openstack.org/api/openstack-object-storage/1.0/content/

For more information come hang out in #openstack-swift on freenode.

Thanks,

The Swift Development Team