514cb598fb
The mClock scheduler's cost model for HDDs/SSDs is modified and now
represents the cost of an IO in terms of bytes.
The cost parameters, namely, osd_mclock_cost_per_io_usec_[hdd|ssd]
and osd_mclock_cost_per_byte_usec_[hdd|ssd] which represent the cost
of an IO in secs are inaccurate and therefore removed.
The new model considers the following aspects of an osd to calculate
the cost of an IO:
- osd_mclock_max_capacity_iops_[hdd|ssd] (existing option)
The measured random write IOPS at 4 KiB block size. This is
measured during OSD boot-up using OSD bench tool.
- osd_mclock_max_sequential_bandwidth_[hdd|ssd] (new config option)
The maximum sequential bandwidth of of the underlying device.
For HDDs, 150 MiB/s is considered, and for SSDs 750 MiB/s is
considered in the cost calculation.
The following important changes are made to arrive at the overall
cost of an IO,
1. Represent QoS reservation and limit config parameter as proportion:
The reservation and limit parameters are now set in terms of a
proportion of the OSD's max IOPS capacity. The earlier representation
was in terms of IOPS per OSD shard which required the user to perform
calculations before setting the parameter. Representing the
reservation and limit in terms of proportions is much more intuitive
and simpler for a user.
2. Cost per IO Calculation:
Using the above config options, osd_bandwidth_cost_per_io for the osd is
calculated and set. It is the ratio of the max sequential bandwidth and
the max random write iops of the osd. It is a constant and represents the
base cost of an IO in terms of bytes. This is added to the actual size of
the IO(in bytes) to represent the overall cost of the IO operation.See
mClockScheduler::calc_scaled_cost().
3. Cost calculation in Bytes:
The settings for reservation and limit in terms a fraction of the OSD's
maximum IOPS capacity is converted to Bytes/sec before updating the
mClock server's ClientInfo structure. This is done for each OSD op shard
using osd_bandwidth_capacity_per_shard shown below:
(res|lim) = (IOPS proportion) * osd_bandwidth_capacity_per_shard
(Bytes/sec) (unitless) (bytes/sec)
The above result is updated within the mClock server's ClientInfo
structure for different op_scheduler_class operations. See
mClockScheduler::ClientRegistry::update_from_config().
The overall cost of an IO operation (in secs) is finally determined
during the tag calculations performed in the mClock server. See
crimson::dmclock::RequestTag::tag_calc() for more details.
4. Profile Allocations:
Optimize mClock profile allocations due to the change in the cost model
and lower recovery cost.
5. Modify standalone tests to reflect the change in the QoS config
parameter representation of reservation and limit options.
Fixes: https://tracker.ceph.com/issues/58529
Fixes: https://tracker.ceph.com/issues/59080
Signed-off-by: Samuel Just <sjust@redhat.com>
Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>
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| ceph-menv | ||
| ceph-object-corpus@038c72b5ac | ||
| cmake/modules | ||
| debian | ||
| doc | ||
| etc | ||
| examples | ||
| fusetrace | ||
| keys | ||
| man | ||
| mirroring | ||
| monitoring | ||
| qa | ||
| selinux | ||
| share | ||
| src | ||
| sudoers.d | ||
| systemd | ||
| udev | ||
| .gitattributes | ||
| .githubmap | ||
| .gitignore | ||
| .gitleaks.toml | ||
| .gitmodule_mirrors | ||
| .gitmodules | ||
| .mailmap | ||
| .organizationmap | ||
| .peoplemap | ||
| .readthedocs.yml | ||
| AUTHORS | ||
| ceph.spec.in | ||
| CMakeLists.txt | ||
| CodingStyle | ||
| CONTRIBUTING.rst | ||
| COPYING | ||
| COPYING-GPL2 | ||
| COPYING-LGPL2.1 | ||
| COPYING-LGPL3 | ||
| do_cmake.sh | ||
| do_freebsd.sh | ||
| doc_deps.deb.txt | ||
| install-deps.sh | ||
| make-debs.sh | ||
| make-dist | ||
| make-srpm.sh | ||
| mingw_conf.sh | ||
| PendingReleaseNotes | ||
| pom.xml | ||
| README.aix | ||
| README.FreeBSD | ||
| README.md | ||
| README.solaris | ||
| README.windows.rst | ||
| run-make-check.sh | ||
| SECURITY.md | ||
| SubmittingPatches-backports.rst | ||
| SubmittingPatches-kernel.rst | ||
| SubmittingPatches.rst | ||
| win32_build.sh | ||
| win32_deps_build.sh | ||
Ceph - a scalable distributed storage system
Please see https://ceph.com/ for current info.
Contributing Code
Most of Ceph is dual licensed under the LGPL version 2.1 or 3.0. Some miscellaneous code is under a BSD-style license or is public domain. The documentation is licensed under Creative Commons Attribution Share Alike 3.0 (CC-BY-SA-3.0). There are a handful of headers included here that are licensed under the GPL. Please see the file COPYING for a full inventory of licenses by file.
Code contributions must include a valid "Signed-off-by" acknowledging the license for the modified or contributed file. Please see the file SubmittingPatches.rst for details on what that means and on how to generate and submit patches.
We do not require assignment of copyright to contribute code; code is contributed under the terms of the applicable license.
Checking out the source
You can clone from github with
git clone git@github.com:ceph/ceph
or, if you are not a github user,
git clone https://github.com/ceph/ceph.git
Ceph contains many git submodules that need to be checked out with
git submodule update --init --recursive
Build Prerequisites
The list of Debian or RPM packages dependencies can be installed with:
./install-deps.sh
Building Ceph
Note that these instructions are meant for developers who are
compiling the code for development and testing. To build binaries
suitable for installation we recommend you build deb or rpm packages
or refer to the ceph.spec.in or debian/rules to see which
configuration options are specified for production builds.
Build instructions:
./do_cmake.sh
cd build
ninja
(do_cmake.sh now defaults to creating a debug build of ceph that can be up to 5x slower with some workloads. Please pass "-DCMAKE_BUILD_TYPE=RelWithDebInfo" to do_cmake.sh to create a non-debug release.
The number of jobs used by ninja is derived from the number of CPU cores of
the building host if unspecified. Use the -j option to limit the job number
if the build jobs are running out of memory. On average, each job takes around
2.5GiB memory.)
This assumes you make your build dir a subdirectory of the ceph.git
checkout. If you put it elsewhere, just point CEPH_GIT_DIR to the correct
path to the checkout. Any additional CMake args can be specified by setting ARGS
before invoking do_cmake. See cmake options
for more details. Eg.
ARGS="-DCMAKE_C_COMPILER=gcc-7" ./do_cmake.sh
To build only certain targets use:
ninja [target name]
To install:
ninja install
CMake Options
If you run the cmake command by hand, there are many options you can
set with "-D". For example, the option to build the RADOS Gateway is
defaulted to ON. To build without the RADOS Gateway:
cmake -DWITH_RADOSGW=OFF [path to top-level ceph directory]
Another example below is building with debugging and alternate locations for a couple of external dependencies:
cmake -DLEVELDB_PREFIX="/opt/hyperleveldb" \
-DCMAKE_INSTALL_PREFIX=/opt/ceph -DCMAKE_C_FLAGS="-Og -g3 -gdwarf-4" \
..
Ceph has several bundled dependencies such as Boost, RocksDB and Arrow. By
default, cmake will build these bundled dependencies from source instead of
using libraries that are already installed on the system. You can opt-in to
using these system libraries, provided they meet the minimum version required
by Ceph, with cmake options like WITH_SYSTEM_BOOST:
cmake -DWITH_SYSTEM_BOOST=ON [...]
To view an exhaustive list of -D options, you can invoke cmake with:
cmake -LH
If you often pipe ninja to less and would like to maintain the
diagnostic colors for errors and warnings (and if your compiler
supports it), you can invoke cmake with:
cmake -DDIAGNOSTICS_COLOR=always ...
Then you'll get the diagnostic colors when you execute:
ninja | less -R
Other available values for 'DIAGNOSTICS_COLOR' are 'auto' (default) and 'never'.
Building a source tarball
To build a complete source tarball with everything needed to build from source and/or build a (deb or rpm) package, run
./make-dist
This will create a tarball like ceph-$version.tar.bz2 from git. (Ensure that any changes you want to include in your working directory are committed to git.)
Running a test cluster
To run a functional test cluster,
cd build
ninja vstart # builds just enough to run vstart
../src/vstart.sh --debug --new -x --localhost --bluestore
./bin/ceph -s
Almost all of the usual commands are available in the bin/ directory. For example,
./bin/rados -p rbd bench 30 write
./bin/rbd create foo --size 1000
To shut down the test cluster,
../src/stop.sh
To start or stop individual daemons, the sysvinit script can be used:
./bin/init-ceph restart osd.0
./bin/init-ceph stop
Running unit tests
To build and run all tests (in parallel using all processors), use ctest:
cd build
ninja
ctest -j$(nproc)
(Note: Many targets built from src/test are not run using ctest.
Targets starting with "unittest" are run in ninja check and thus can
be run with ctest. Targets starting with "ceph_test" can not, and should
be run by hand.)
When failures occur, look in build/Testing/Temporary for logs.
To build and run all tests and their dependencies without other unnecessary targets in Ceph:
cd build
ninja check -j$(nproc)
To run an individual test manually, run ctest with -R (regex matching):
ctest -R [regex matching test name(s)]
(Note: ctest does not build the test it's running or the dependencies needed
to run it)
To run an individual test manually and see all the tests output, run
ctest with the -V (verbose) flag:
ctest -V -R [regex matching test name(s)]
To run tests manually and run the jobs in parallel, run ctest with
the -j flag:
ctest -j [number of jobs]
There are many other flags you can give ctest for better control
over manual test execution. To view these options run:
man ctest
Building the Documentation
Prerequisites
The list of package dependencies for building the documentation can be
found in doc_deps.deb.txt:
sudo apt-get install `cat doc_deps.deb.txt`
Building the Documentation
To build the documentation, ensure that you are in the top-level
/ceph directory, and execute the build script. For example:
admin/build-doc
Reporting Issues
To report an issue and view existing issues, please visit https://tracker.ceph.com/projects/ceph.