集群存储系统-Vastsky
2010-10-28 15:34:13 
阿炯
Vastsky 是一个基于 Linux 的集群存储系统，提供逻辑卷将分布在网络中的磁盘块聚集起来。Vastsky is a linux-based cluster storage system, which provides logical volumes (linux block devices) to users by aggregating disks over a network.
A vastsky system consists of three kinds of servers:
- storage manager
- head servers
- storage servers
Vastsky assumes that the servers are connected each other by a mostly-flat network. (eg. an ethernet segment)
A storage manager maintains a database which describes physical and logical resources in a system, e.g. servers, disks, logical volumes.It serves xml-rpc based API that operates on resources, e.g. create and attach logical volumes.
Normally there should be only one storage manager on a Vastsky system.Vastsky currently does not provide any redundancy for the storage manager itself. It might be a good idea to consider to use external HA solutions for this.
Head servers run user applications which actually use Vastsky logical volumes.
Storage servers have physical disks which are used to store user data.They are exported over the network and used to provide logical volumes on head servers. Anything which Linux recognizes as a block device can be used as vastsky physical disks.
Redundancy, fault detection and recovery:
Vastsky mirrors user data to three storage servers by default.Vastsky attempts to detect hardware failures including broken disks.
On a failure, the storage manager attempts to reconfigure mirrors by allocating new extents from other disks automatically.
Vastsky can be configured to use two networks (e.g. two independent ethernet segments) for redundancy. When one network is down Vastsky will attempt to use the other network transparently to users.
The storage manager periodically checks if each head and storage servers are responsive. Disks on unresponsive storage servers are considered broken and the mirror reconfiguration mentioned above will happen.
Vastsky provides XML-RPC based API, which allows external monitoring programs report resource failures.
最新版本：3.0
该版本增加对逻辑卷的快照、Eucalyptus EBS 以及 TGT iscsi target的支持，同时内部做了一些重构工作以提升系统稳定性。
项目主页：http://sourceforge.net/projects/vastsky/