Parallax
Parallax is an LSM-based persistent key-value store designed for flash storage devices (SSDs, NVMe). Parallax reduces I/O amplification and increases CPU efficiency using the following mechanism. It categorizes key-value (KV) pairs into three size-based categories: Small, Medium, and Large. Then it applies a different policy for each category. It stores Small KV pairs inside the LSM levels (as RocksDB). It always performs key-value separation for KV pairs (as BlobDB), writing them in a value log, and it uses a garbage collection (GC) mechanism for the value log. For medium KV pairs, it uses a hybrid policy: It performs KV separation up to the semi-last levels and then stores them in place to bulk-free space without using GC.
You can find more details in the paper:
Giorgos Xanthakis, Giorgos Saloustros, Nikos Batsaras, Anastasios Papagiannis, and Angelos Bilas. 2021. Parallax: Hybrid Key-Value Placement in LSM-based Key-Value Stores. In Proceedings of the ACM Symposium on Cloud Computing (SoCC '21). Association for Computing Machinery, New York, NY, USA, 305–318. DOI:https://doi.org/10.1145/3472883.3487012
Building Parallax
Installing Dependencies on Ubuntu 18.04 LTS
Parallax requires CMake version >= 3.11.0. On Ubuntu, you need to add the following repository to get the latest stable version of CMake:
wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | sudo apt-key add -
sudo apt-add-repository 'deb https://apt.kitware.com/ubuntu/ bionic main'
sudo apt update
Run the following command with superuser privileges:
sudo apt install libnuma-dev
For the build tools and compiler:
sudo apt install cmake build-essential
Installing Depedencies on Centos/RHEL 7
Parallax requires CMake version >= 3.11.0. On Centos/RHEL this is supplied from the EPEL repository and can be installed with:
sudo yum install cmake3 kernel-devel gcc-c++ numactl-devel boost-devel
Build Configuration
Compilation is done using the gcc/clang compilers, provided by the gcc/clang packages in most Linux distributions. To configure Parallax's build systems and build it run the commands:
mkdir build
cd build
cmake ..
make
On Centos/RHEL 7, replace the cmake command with the cmake3 command supplied
from the EPEL package of the same name.
Build Configuration Parameters
The CMake scripts provided support two build configurations; "Release" and "Debug". The Debug configuration enables the "-g" option during compilation to allow debugging. The build configuration can be defined as a parameter to the cmake call as follows:
cmake3 .. -DCMAKE_BUILD_TYPE="Debug|Release" .
The default build configuration is "Debug".
The "Release" build disables warnings and enables optimizations.
Build Targets
- build/lib/libparallax.a/so - Parallax library
- build/YCSB-CXX/ycsb-edb - Standalone Parallax YCSB benchmark
- build/tests/ - Tests for Parallax
Build Package
You can install Parallax in your standard path using cmake.
Run cpack -G "RPM" inside the build folder to create an RPM file.
Run cpack -G "DEB" inside the build folder to create a DEB file.
Run sudo rpm -Uvh parallax.rpm using the rpm file produced from the cpack command.
Run sudo dpkg -i parallax.deb using the deb filed produced from the cpack command.
Run make install inside the build folder to install Parallax without producing an RPM or DEB file.
Run make uninstall inside the build folder to remove files installed by make install. (Directories are not deleted)
In case you want to link statically without using cmake check scripts/pack-staticlib.py to create a single binary called libparallax2.a and link with it.
Acknowledgements
We thankfully acknowledge the support of the European Commission under the Horizon 2020 Framework Programme for Research and Innovation through the projects EVOLVE (Grant Agreement ID: 825061). This work is (also) partly supported by project EUPEX, which has received funding from the European High-Performance Computing Joint Undertaking (JU) under grant agreement No 101033975. The JU receives support from the European Union's Horizon 2020 re-search and innovation programme and France, Germany, Italy, Greece, United Kingdom, Czech Republic, Croatia.