Does RAM really can be the new disk as suggested in this article? My take on this question is "No". First of all, making RAM to be the new disk will not help under the current computer architecture. Secondly, having disk on RAM technology is not economically feasible.
The current computer architecture follows Von Neumann architecture. Under the Von Neumann Architecture and its variants, hard disk serves memory purpose as a storage, RAM serves as temporary memory with very fast (compared to the hard disk) I/O performance. Using RAM technology to speed up disk I/O is good but it will have limited overall performance gain for an application because it only speeds up the throughput between the disk and RAM. However, the actual performance bottleneck under this computer architecture is the limited throughput between the CPU and memory compared to the amount of memory. So improving disk performance will not speed up the application throughput.
The most promising RAM technology that can be the new disk is (solid-state drive) SSD but the cost/performance ratio is still high compared to the traditional HDD with the same storage capacity for many workload scenarios. This is explained very well in this paper. If the disk is used only as a storage medium (what it should be), SSD solutions are too expensive to be justifiable in many situations. So we won't see a big adoption of SSD as a enterprise-server storage medium in a short future. IMHO, it might not even happen.
From the application perspective, if we adopt data partitioning as I suggested in the other post, the disk will be used as the storage and RAM will be used as the system of record. So during the application runtime, the application will not access the disk and therefore, we achieve the best performance we can under the current computer architecture without introducing expensive hardware (scale-up). This is probably the only way to go to speed up the application in the near future.
No comments:
Post a Comment