关于nas/nfs 文件系统与asm

参考自:Creating File Devices On NAS/NFS FileSystems For ASM Diskgroups. (文档 ID 1620238.1)

Note: Caution should be exercised when considering using NFS storage, in an Oracle database environment, with ASM. 
In general, such configurations should be avoided or at least carefully considered. 
The issue is that to prevent data corruption, NFS file systems must be hard-mounted. 
Hard mounting means that the database or an ASM instance must wait indefinitely when an NFS server, 
or the communications link it operates over, becomes unavailable. 
This means that ASM cannot effectively provide data mirroring. 


Situations where NFS on ASM may be a reasonable option include:
1.Using NFS for an ASM Quorum Failure Group, as is often done with Extended Clusters. 
  NFS on Quorum Failure Groups with 11.2.0.4 or later, does not need, or should not use hard NFS mounts.
2.Situations where reliable access to NFS service can be assured.
3.When using NFS storage only for an External Redundancy Diskgroup.
4.Situations where the lost of ASM file access for an extended period is not critical.

该文章还有几个值得参考的知识点:

第一点:

Mount Options for Oracle files when used with NFS on NAS devices (Doc ID 359515.1)

第二点:

asm实例默认的搜索路径:

Linux: /dev/raw/* and/or ORCL:* 
AIX: /dev/rhdisk*
HP-UX: /dev/rdisk/*
Solaris: /dev/rdsk/*
Windows: \\.\ORCLDISKn

另外一篇值得参考的文章:

How To Create ASM Diskgroups using NFS/NAS Files? (文档 ID 731775.1)