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5fa866223d
Keeping the mutations coming from the streaming process as mutations like any other have a number of advantages - and that's why we do it. However, this makes it impossible for Seastar's I/O scheduler to differentiate between incoming requests from clients, and those who are arriving from peers in the streaming process. As a result, if the streaming mutations consume a significant fraction of the total mutations, and we happen to be using the disk at its limits, we are in no position to provide any guarantees - defeating the whole purpose of the scheduler. To implement that, we'll keep a separate set of memtables that will contain only streaming mutations. We don't have to do it this way, but doing so makes life a lot easier. In particular, to write an SSTable, our API requires (because the filter requires), that a good estimate on the number of partitions is informed in advance. The partitions also need to be sorted. We could write mutations directly to disk, but the above conditions couldn't be met without significant effort. In particular, because mutations can be arriving from multiple peer nodes, we can't really sort them without keeping a staging area anyway. Signed-off-by: Glauber Costa <glauber@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 gcc-c++ gnutls-devel ninja-build ragel libaio-devel cryptopp-devel xfsprogs-devel numactl-devel hwloc-devel libpciaccess-devel libxml2-devel python3-pyparsing
- Build Scylla
./configure.py --mode=release --with=scylla --disable-xen
ninja-build 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/.