lvm ssd cache with hwraid and battery backup

[sahostking]

hi

I have 2x ssds and 4x hdd.

Also currently setup using lvm and raid1 ssd and raid10 sata x4.

I am using hwraid controller with battery backup in writeback.

Question is can I still create ssd cache using the ssds?

 

[wolfgang]

Question is can I still create ssd cache using the ssds?

Yes but for what?
You have a Raid cache in your HW Raid what use DRAM.
No ssd is faster than DRAM.

 

[sahostking]

Was wondering the same but wasnt so sure yet.

Thanks

 

[sahostking]

One thing though I cannot get my head around. Why has the LSI controller got something called CacheCade SSD Caching?

Is that still slower than using BBU with writeback? I've never enabled that before for testing so was wondering what that option is and why would it be there if BBU in writeback mode was available?

 

[wolfgang]

CacheCade SSD Caching?

This is a read only cache.
On virtualization you have to many hot data.
So you would need a very huge cache to speed it up.