在线数据存储 S3QL 1.2 发布

     <p>S3QL 是个用来在线存储数据的文件系统，支持 Amazon S3 、SFTP 服务器等。<br /> S3QL 1.2 发布了，新增了更多存储后端的支持（Google存储和通用S3兼容存储）；修复了数据被破坏的bug；重写了后端模块可更好的处理网络错误的情况；同时还包括如下改进：</p>    <ul>     <li>A bucket can now hold several filesystems. </li>     <li>The local backend only uses half as many files as before. </li>     <li>The sftp backend has been dropped. </li>     <li>Logging to syslog is possible. </li>     <li>Faster fsck. </li>     <li>A smaller metadata database. </li>     <li>FUSE4BSD compatibility<br /> </li>    </ul>    <br />    <h2>Features</h2>    <ul>     <li><strong>Transparency.</strong> Conceptually, S3QL is indistinguishable from a local file system. For example, it supports hardlinks, symlinks, ACLs and standard unix permissions, extended attributes and file sizes up to 2 TB. </li>    </ul>    <ul>     <li><strong>Dynamic Size.</strong> The size of an S3QL file system grows and shrinks dynamically as required. </li>    </ul>    <ul>     <li><strong>Compression.</strong> Before storage, all data may compressed with the LZMA, bzip2 or deflate (gzip) algorithm. </li>    </ul>    <ul>     <li><strong>Encryption.</strong> After compression (but before upload), all data can AES encrypted with a 256 bit key. An additional SHA256 HMAC checksum is used to protect the data against manipulation. </li>    </ul>    <ul>     <li><strong>Data De-duplication.</strong> If several files have identical contents, the redundant data will be stored only once. This works across all files stored in the file system, and also if only some parts of the files are identical while other parts differ. </li>    </ul>    <ul>     <li><strong>Immutable Trees.</strong> Directory trees can be made immutable, so that their contents can no longer be changed in any way whatsoever. This can be used to ensure that backups can not be modified after they have been made. </li>    </ul>    <ul>     <li><strong>Copy-on-Write/Snapshotting.</strong> S3QL can replicate entire directory trees without using any additional storage space. Only if one of the copies is modified, the part of the data that has been modified will take up additional storage space. This can be used to create intelligent snapshots that preserve the state of a directory at different points in time using a minimum amount of space. </li>    </ul>    <ul>     <li><strong>High Performance independent of network latency.</strong> All operations that do not write or read file contents (like creating directories or moving, renaming, and changing permissions of files and directories) are very fast because they are carried out without any network transactions. S3QL achieves this by saving the entire file and directory structure in a database. This database is locally cached and the remote copy updated asynchronously. </li>    </ul>    <ul>     <li><strong>Support for low bandwidth connections.</strong> S3QL splits file contents into smaller blocks and caches blocks locally. This minimizes both the number of network transactions required for reading and writing data, and the amount of data that has to be transferred when only parts of a file are read or written. </li>    </ul> 项目地址：    <a href="/misc/goto?guid=4958192052972938978" target="_blank">http://code.google.com/p/s3ql/</a>    <br />