Oracle DB with SSD

Question

I have a HP DL 380 G7 + 2 Xeon Processors + 12GB DDR + 6HDD 10k RAID5
I know that RAID 5 is not the best choise for a Oracle database with writing, but it's cheaper than RAID 10.
But the Database was smooth, no locks, relative fast, but there is a new legislation that forces anyone to have a certificated application. This certificated application records everything you do, every click, every document you create, modify or read. Has you can imagine this made the database writing 10 to 100, and know it's getting slower.
Instead of going for RAID 10, i was thinking about SSD Technology.
Would it work to put a HP SSD/HD on the server for caching? I could put Redo logs, Temp, control files, etc inside this drive, to avoid too much writing processes on the SAS Drives.
This drives are very very fast, but they have a low life expectancy, if i'm not mistaken it's about 3 to 5 years with lots of writing.
What is you opinion? Could it work? Should i forget this and go straight to RAID 10?
Regards.

Answer 1

RAID 5 with 3 disks runs slow.
So i put 5 disks and 1 spare.
I still have 2 more disks i can increase in the server. I could get 2 more disk and use RAID 1, and place the Redo logs.
I used DB-Tuna, and i checked that some update SQL statements lock the DB. These are very powerful statements that update lots of tables. This only happens when the users are introducing invoice with lots of products for one company.
This company is very complex, there is a major company and 7 more small companies inside.
One company receives all the products and then distributes for all the other smaller companies. This is the operation that usually locks the DB. There is lots of updates, and when they are doing this operation, it locks all the other users.
Beside this operation, the database works better, but not fast enough.
I increased the Redo log size up to 100mb, it started to run better, but not efficient enough. I'm afraid to increase too much, and when the switch occur it can lock the DB for a long time.
I suspect that the SQL statement is not at it's best, but the programers said that they have the same application running in the other companies that work well.
I don't have how to confirm this, so i have to do the best that i can.
Like i said before, this could be because of the certification of the application, because before this, the database was running great. When we installed the new application, it started all of this problems, the disks are working harder than ever, everything is being recorded for the financial department.
Increasing 2 more SAS disks for redo logs is a great idea. I'm not sure if this RAID controller can control 2 different raids at the same time, and if it can, is it efficient? Must look at the controllers manual.