d317888a7e
We are soon going to put servers with a high ratio of disk to CPU
into production as object servers. One of our concerns with this
configuration is that the object auditor would take too long to
complete its audit cycle. Therefore we decided to parallelise
the auditor.
The auditor already uses fork(), so we decided to use the parallel
model from the replicator. Concurrency is set by the concurrency
parameter in the auditor stanza, which sets the number of parallel
checksum auditors. The actual number of parallel auditing processes
is concurrency + 1 if zero_byte_fps is non-zero.
Only one ZBF process is forked, and a new ZBF process is forked as
soon as the current ZBF process finishes. Thus the last process
running will always be a ZBF process.
Both forever and once modes are parallelised.
Each checksum auditor process submits a nested dictionary with keys
{'object_auditor_stats_ALL': {'diskn': {..}}} to dump_recon_cache
so that the object_auditor_stats_ALL dict in recon cache consists
of individual sub-dicts for each of the object disks on the server.
The recon cache is no different to before when the checksum auditor
is run in serial mode. When swift-recon is run, it sums the stats
for the individual disks.
DocImpact
Change-Id: I0ce3db57a43e482d4be351cc522fc9060af6e2d3
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.
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