Redologs on ASM but not archivelogs

Question

Hello,
for the same database, is correct to have redolog on ASM when Archivelogs still on filesystem ?
Thank you.

Answer 1

Hello,
There is no correct answer to this problem. It depends on your strategy. The main advantages of ASM are simplicity and unbuffered I/O so make use of them.
Redo log need both write and read operations aside from archiving (bulk read). On the other side Archived Redo rarely need read operations after its initial bulk write, unless you do frequent recovery. So, you don't want to buffer archived redo logs.
Both can take advantage of ASM feature, so you can put both on ASM.
Later on, if are not satisfy with its performance, you can add more disks to ASM. It is easier to manage than putting archived redo logs on file system and the rest on ASM.
In my opinion it is more important to define strategy of storage tiers within the ASM itself. You can then map each tier to ASM disk group. For example for fast read/normal write you can create tier1 with RAID 1 or RAID 10 and map this tier to ASM disk group. You can then put OLTP/DSS data files into this tier (because they requires fast read). You can create other tiers according to your need based on this example.
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