不建议把Oracle redo存放在SSD上
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不建议把Oracle redo存放在SSD上
不建议把Oracle redo存放在SSD上
不建议把redo存放在SSD上，主要原因在于 SSD的优势为读取速度，其对 随机写也有一定优化，但 redo日志的IO类型主要为顺序写而非随机写。
oracle 官方Support文档 《How to Minimize Waits for ‘Log File Sync’ (Doc ID 857576.1)》指出不建议把redo 存放在RAID 5或者 Solid State Disk (SSD)上。
以下是REDO存放在SAS和SSD上的性能对比图（越短越好），可以看到当并发较高时SSD甚至比普通SAS要差：
一般建议用户考虑将以下几类文件存放在SSD上：
- 读写最多的表空间的数据文件,包括Undo
- 临时表空间
Comments
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大山与人 says
刘大，这个oracle文档是不是变更了，怎么没看到你的截图说的呢，反而说放在ssd上能减少延迟什么的，迷糊了If you have dedicated high availability storage technologies tuned for write then use those in accordance to the vendors instructions. For example, it is recommended to configure zpools for redo log files with a ZFS SLOG (Separate LOG). Adding a SLOG to a zpool dedicated to redo log files can reduce latency issues with log transactions. Also putting the SLOG on an SSD (Solid State Disk) will reduce redo log latency further. This will help improve the performance of synchronous writes. See:
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