Kevin__Zhang 发表于 2012-2-27 12:55
upup
RAID10是先做镜象，然后再做条带。
RAID01则是先做条带，然后再做镜象
其实主要是在安全性上有一些不同，如果磁盘不坏的话，性能应该是一样的
但还是推荐RAID10
1.这个问题RAID0的作用就是条带，分散I/O，而你说的降低磁盘读写效率应该指的是有效磁盘数的使用吧，这是RAID1的作用，为了安全牺牲一些空间还是值当的，如果不考虑成本的因素应该说不存在性能丢失我觉得
2.ASM的研究也不深，但是我觉得得分两步说。首先在ASM是external redundancy的时候，它本身应该也是有条带的功能的，只不过不具备FAIL GROUP。那么应该是说也是有RAID0的作用的
当你用normal redundancy或high redundancy的时候应该就是既有RAID0也有RAID1的功能了。如果底层还有RAID的话我想就是双保险了
3.
Normal redundancy（1 OCR and 2 copies ）In a normal redundancy disk group, to increase performance and reliability,Automatic Storage Management by default uses two-way mirroring. A normalredundancy disk group requires a minimum of two disk devices (or twofailure groups). The effective disk space in a normal redundancy disk group ishalf the sum of the disk space in all of its devices.For Oracle Clusterware files, Normal redundancy disk groups provide 3voting disk files, 1 OCR and 2 copies (one primary and one secondary mirror).With normal redundancy, the cluster can survive the loss of one failure group.For most installations, Oracle recommends that you select normal redundancy.1.2.3 HIGH模式
High redundancy（1 OCR and 3 copies ）In a high redundancy disk group, Automatic Storage Management usesthree-way mirroring to increase performance and provide the highest level ofreliability. A high redundancy disk group requires a minimum of three diskdevices (or three failure groups). The effective disk space in a high redundancydisk group is one-third the sum of the disk space in all of its devices.For Oracle Clusterware files, High redundancy disk groups provide 5 votingdisk files, 1 OCR and 3 copies (one primary and two secondary mirrors). Withhigh redundancy, the cluster can survive the loss of two failure groups.While high redundancy disk groups do provide a high level of data protection,you should consider the greater cost of additional storage devices beforedeciding to select high redundancy disk groups. 文档里描述了这两个的区别主要在磁盘的开销上，并没有提到性能的区别。所以应该没什么不同说的不一定对，仅代表我的看法
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