LSI 9271-8i settings help

[Philj]

Hi

I have an LSI 9271-8i without a BBU. I have the following settings applied:

Write Policy: Write Back
Read Policy: Always Read Ahead
IO Policy: Direct IO
Access Policy: Read Write
Disk Cache Policy: Disabled
Background Initialisation: Enabled

What do you think of these settings? Should I may any changes for better performance?

Many thanks

Phil

 

[asheron42]

For IO Policy, are you transferring mostly large files or mostly small files? DirectIO is faster when the size of the file is known to exceed the cache size. But for most usage, a cached IO will have better performance.
The read policy set to always is also good for predicting longer file pulls, but for short reads, like a DB read then an adaptive policy is more performant and doesn't utilize as much of the card cache.
I would set the disk cache policy to on.

The reason to set write through and disk cache policy to off is for data integrity. A power loss where the write has been committed to cache, but not to disk will have a write failure. This is a short window scenario, but pretty much required for enterprise, since they would have a constant amount of data go through. It's fine for home use as well, because we're talking about saving ms of latency. If you have a work SLA that needs the faster latency, like tons of individual DB commits in a small window, then it makes a difference to choose write back.