读gfs2官方文档

reading link:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Global_File_System_2/ch-overview-GFS2.html#s1-ov-newfeatures-GFS2

特点

1. Red Hat does not support using GFS2 for cluster file system deployments greater than 16 nodes.
   

2. However, the current supported maximum size of a GFS2 file system for 64-bit hardware is 100TB.

3. The current supported maximum size of a GFS2 file system for 32-bit hardware is 16TB

4. Asymmetric cluster configurations in which some nodes have access to the shared storage and others do not are not supported.

5. The rule of thumb with GFS2 is that smaller is better: it is better to have 10 1TB file systems than one 10TB file system.

6. With GFS2, you can add journals on the fly.

7. While there is no defragmentation tool for GFS2 on Red Hat Enterprise Linux, you can defragment individual files by identifying them with the filefrag tool, copying them to temporary files, and renaming the temporary files to replace the originals.

8. Newer versions of GFS2 include the fallocate(1) system call, which you can use to preallocate blocks of data

9. Red Hat recommends that you allow a period of around 8-12 weeks of testing on new installations in order to test the system and ensure that it is working at the required performance level.

10.    Mount Options: noatime and nodiratime

11. Security Enhanced Linux (SELinux) is highly recommended for security reasons in most situations, but it is not supported for use with GFS2.

12. Setting Up NFS Over GFS2

13. Samba (SMB or Windows) File Serving Over GFS2

14. Red Hat performs most quality, sanity, and performance tests on SAN storage with Fibre Channel interconnect

15. Suspending Activity on a File System

16. reltime
    

软件包

根据文档一步步走，应该问题不大。 需要注意将lvm的锁类型lock_type=1改成3，表示集群锁！

与ocfs2相比，一点感觉而已：

- 这篇文档写得不错，多了性能和调试相关的话题，说的比较接地气；

- 易用性不如ocfs2;

- 限制多，gfs2说最多支持16结点，ocfs2说能支持64个结点； ocfs2的本地模式很方便； ocfs2的工具集组织，命名都比较正规，gfs2乱七八遭；

- ocfs2自带原生DLM，即o2cb， 也支持dlm;

- gfs2貌似只有红帽在玩，而ocfs2有oracle，SUSE， 华为，华三几个公司在玩；