第 2 章 考虑在设备映射器多路径中使用 GNBD
带设备映射器多路径的 GNBD 允许您配置多个 GNBD 服务器节点(将 GNBD 导出到 GFS 节点的节点)来为存储设备提供冗余路径。GNBD 服务器节点依次通过冗余 GNBD 为 GFS 节点显示多存储路径。当使用带设备映射器多路径的 GNBD 时,如果某个 GNBD 服务器节点不可用,另一个 GNBD 服务器节点就提供可访问存储设备的 GFS 节点。
如果您正在使用带设备映射器多路径的 GNBD,您需要考虑以下几点:
- Linux page caching, as desribed in 第 2.1 节 “Linux 页面缓存”.
- Fencing GNBD server nodes, as described in 第 2.2 节 “栅栏 GNBD 服务器节点”.
- GNBD device names; export names for GNBD devices must be unique. Additionally, you must specify the
-u
or-U
when using thegnbd_export
command. Exporting GNBD devices is described in 第 3 章 GNBD 驱动程序及命令用法.
2.1. Linux 页面缓存
For GNBD with device-mapper multipath, do not specify Linux page caching (the
-c
option of the gnbd_export
command). All GNBDs that are part of a logical volume must run with caching disabled. Data corruption occurs if the GNBDs are run with caching enabled. Refer to 第 3.1 节 “从服务器中导出 GNBD” for more information about using the gnbd_export
command for GNBD with device-mapper multipath.