DSS

Distributed Storage Service (DSS) is a basic component. It supports access and management of raw devices, covering API operations and O&M tools for creating, deleting, and accessing volume groups, volumes, directories, and files. It also supports multi-node synchronization of the same file metadata to share the database storage architecture.

1. Project Description

1. Programming language: C

2. Compilation tool: CMake (recommended) or Make

3. Directories:

• DSS: the main directory. The CMakeLists.txt file is the main project entry.
• src: the source code directory. Common functions are grouped by sub-directory.
• build: the project building script

2. Using Ceph

1. Creating a Ceph Block Device (Storage Pool and Image)

• Create a storage pool: ceph osd pool create dsspool 64 64
• Create an image: rbd create dssimage --size 10240MB --pool dsspool --image-format 2 --image-feature layering
• Mount the image: rbd map dsspool/dssimage

2. Writing Ceph Configurations During DSS Initialization

• DSSDATA=/dev/rbd0
• DSSHOME=${DSSDATA}
• echo "VOLUME_TYPES=${DSSDATA}=1" > ${DSSHOME}/cfg/dss_inst.ini
• echo "POOL_NAMES=${DSSDATA}=dsspool" >> ${DSSHOME}/cfg/dss_inst.ini
• echo "IMAGE_NAMES=${DSSDATA}=dssimage" >> ${DSSHOME}/cfg/dss_inst.ini
• echo "CEPH_CONFIG=/etc/ceph/ceph.conf" >> ${DSSHOME}/cfg/dss_inst.ini
• DSSDATA=/dev/rbd0 is the mounted Ceph block device.
• POOL_NAMES is the storage pool configuration, in the format of /dev/rbd0=dsspool.
• IMAGE_NAMES is the image configuration, in the format of /dev/rbd0=dssimage.
• CEPH_CONFIG is the configuration file of the Ceph cluster. It defaults to /etc/ceph/ceph.conf.

3. Compilation Guide

1. OS and Software Dependencies

The following OSs are supported:

• CentOS 7.6 (x86)
• openEuler 20.03 LTS
• openEuler 22.03 LTS
• openEuler 24.03 LTS

For details about how to adapt to other OSs, see the openGauss compilation guide.

2. Downloading DSS

Download DSS from the open-source community.

3. Compiling Code

Use DSS/build/linux/opengauss/build.sh to compile the code. The following table describes the parameters.

Option	Parameter	Description
-3rd	[binarylibs path]	Specifies the binarylibs path. It must be an absolute path.
-m	[version_mode]	Specifies the target version of the compilation. It can be Debug or Release (default).
-t	[build_tool]	Specifies the compilation tool, which can be cmake (default) or make.

Run the following command to perform compilation:
[user@linux ]$ sh build.sh -3rd [binarylibs path] -m Release -t cmake
After the compilation is complete, the dynamic library is generated under the DSS/output/lib directory.