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83b004b2fb
Originally, lsa allocated each segment independently what could result in high memory fragmentation. As a result many compaction and eviction passes may be needed to release a sufficiently big contiguous memory block. These problems are solved by introduction of segment zones, contiguous groups of segments. All segments are allocated from zones and the algorithm tries to keep the number of zones to a minimum. Moreover, segments can be migrated between zones or inside a zone in order to deal with fragmentation inside zone. Segment zones can be shrunk but cannot grow. Segment pool keeps a tree containing all zones ordered by their base addresses. This tree is used only by the memory reclamer. There is also a list of zones that have at least one free segments that is used during allocation. Segment allocation doesn't have any preferences which segment (and zone) to choose. Each zone contains a free list of unused segments. If there are no zones with free segments a new one is created. Segment reclamation migrates segments from the zones higher in memory to the ones at lower addresses. The remaining zones are shrunk until the requested number of segments is reclaimed. Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
#Scylla
##Building Scylla
In addition to required packages by Seastar, the following packages are required by Scylla.
Submodules
Scylla uses submodules, so make sure you pull the submodules first by doing:
git submodule init
git submodule update --recursive
Building and Running Scylla on Fedora
- Installing required packages:
sudo yum install yaml-cpp-devel lz4-devel zlib-devel snappy-devel jsoncpp-devel thrift-devel antlr3-tool antlr3-C++-devel libasan libubsan
- Build Scylla
./configure.py --mode=release --with=scylla --disable-xen
ninja build/release/scylla -j2 # you can use more cpus if you have tons of RAM
- Run Scylla
./build/release/scylla
- run Scylla with one CPU and ./tmp as data directory
./build/release/scylla --datadir tmp --commitlog-directory tmp --smp 1
- For more run options:
./build/release/scylla --help
Building Fedora RPM
As a pre-requisite, you need to install Mock on your machine:
# Install mock:
sudo yum install mock
# Add user to the "mock" group:
usermod -a -G mock $USER && newgrp mock
Then, to build an RPM, run:
./dist/redhat/build_rpm.sh
The built RPM is stored in /var/lib/mock/<configuration>/result directory.
For example, on Fedora 21 mock reports the following:
INFO: Done(scylla-server-0.00-1.fc21.src.rpm) Config(default) 20 minutes 7 seconds
INFO: Results and/or logs in: /var/lib/mock/fedora-21-x86_64/result
Building Fedora-based Docker image
Build a Docker image with:
cd dist/docker
docker build -t <image-name> .
Run the image with:
docker run -p $(hostname -i):9042:9042 -i -t <image name>
Contributing to Scylla
Do not send pull requests.
Send patches to the mailing list address scylladb-dev@googlegroups.com. Be sure to subscribe.
In order for your patches to be merged, you must sign the Contributor's License Agreement, protecting your rights and ours. See http://www.scylladb.com/opensource/cla/.