IWEB .0001 Best of Both Worlds – Hybrid Systems
The most cost effective method of utilizing SSDs is a combination of the two methods above in conjunction with HDDs to provide the bulk of the capacity. Putting together a hybrid system requires a more specific understanding of the application environment, but can deliver the most dramatic results.
For example, let’s say we have a database application where overall performance is important, but the order entry portion is critical to the business and needs to be very fast. The overall application databases are very large (12TB), with the order entry portion consisting of around 200GB. A possible configuration would be to configure six SSDs along with 22 1TB SATA drives. You would configure the drives as follows:
• 1 200GB SSD (L2ARC)
• 1 200GB SSD (ZIL)
• 4 400GB SSDs (Hight-Perf-Pool)
• 14 1TB SATA drives (DB-Capacity-Pool)
• 8 1TB SATA drives (Gen-Pool)
With this configuration, all database logs plus the order entry database are put into volumes within the High-Perf-Pool while all other databases are put into the DB-Capacity-Pool. Since there are dedicated SSDs for both a level 2 cache and for the write indexes, overall performance will be 2 to 3 times as good for the general database, and the critical order entry database gets the full benefit of running all on SSDs. The Gen-Pool is used for all other applications and general file sharing, so as to not interfere with the database I/Os.
