====== Object storage is an approach to storage where data is combined with rich metadata in order to preserve information about both the context and the content of the data.

The metadata present in Object Storage gives users the context and content information they need to properly manage and access unstructured data. They can easily search for data without knowing specific filenames, dates or traditional file designations. They can also use the metadata to apply policies for routing, retention and deletion as well as automate storage management.

HOSS is a highly available, scalable, manageable,distributed object storage system based on HDFS. Consider the scalability, reliability, availability and consistency of object-based storage, HOSS adopts centralized metadata management simplifying the whole storage. In addition, for disadvantages of centralized metadata management, HOSS uses a hot-aware heterogeneous metadata management model. The model defines the hotness of metadata, and according to hot, it migrates metadata to different storage devices, such as DRAM and SSD. In heterogeneous metadata storage, HOSS introduces multi-dimensional storage structure to manage the metadata on the SSD based on accessed dynamic characteristics and static characteristics of object metadata. The structure simplifies the access of object data, but also improves the utilization of SSD.

• Heterogeneous metadata management.
• Multi-dimensional storage structure.
• High performace, scalability, reliability and consistency.
• Very easy to use.
• Support object put/get/delete/list.
• Support hot object metadata in memory cache(a.k.a. hot-aware cache).
• Support small objects combining.

cd $HOSS_HOME 
ant clean & ant

start-hoss.sh 
stop-hoss.sh 

• Object Put Example

public static void write(String objName, String content) throws IOException {
		HosObject hosObject = new HosObject(objName);
		FSDataOutputStream out = hosObject.getWriter();
		if (null != out){
			out.writeBytes(content);
			hosObject.close();
		}
	}

• Object Put Example

public static void write(String objName, String content) throws IOException {
		HosObject hosObject = new HosObject(objName);
		FSDataOutputStream out = hosObject.getWriter();
		if (null != out){
			out.writeBytes(content);
			hosObject.close();
		}
	}

• Object Get Example

public static void read(String objName) throws IOException {
		HosObject hosObject = new HosObject(objName);
		FSDataInputStream in = hosObject.getReader();
		byte[] ioBuffer = new byte[1024];  
        int readLen = in.read(ioBuffer); 
        System.out.print(objName + " contents :");
        while(readLen!=-1)  
        {  
            System.out.print(new String(ioBuffer, 0, readLen));  
            readLen = in.read(ioBuffer);  
        }  
		hosObject.close();
	}

• Object Delete Example

public static void delete(String objName) throws IOException {
		HosObject hosObject = new HosObject(objName);
		hosObject.deleteObject();
	}

• List Objects Example

public static void list() {
		ClientProtocol client  = HosClient.client();
		Text namelist = client.listObjects();
		String[] names = namelist.toString().split("\t");
		System.out.println("object name # position");
		for(String name: names) {
			System.out.println(name);
		}
	}

• Top k Hot Object Example

public static void topHot(int top) {
		lientProtocol client  = HosClient.client();
		Text namelist = client.topHotObject(top);
		String[] names = namelist.toString().split("\t");
		System.out.println("object name # hotness");
		for(String name: names) {
			System.out.println(name);
		}
	}

For bugs and feature requests, please create an issue. Pull requests and stars are always welcome.

see details "http://cddesire.github.io/hoss/"