http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9005207&source=rss_topic19

Its replaced the traditional hard drives with solid state devices operating at approx 250 times the speed of a hard disk. They’re touting it as the fastest storage in the world.

In situations like this, it would be handy to be able to replace some of the magnetic disks with plug-compatible SSDs, build a new raidgroup, relocate hot-spots, etc …and try again.

From my experience, it is very difficult to go back to a ‘slow’ solution, providing the benefit can be easily demonstrated and the cost is right. Historically, this was the case with some of the old I/O caching solutions, going back to PDP11 days.

On Hitachi boxes the destaging process starts picking up the pace at the around the 40% mark, basically shovelling data off to disk at a faster rate. Once this 40% mark was breached, the performance of the XP took an absolute nose dive. Now although this will no doubt have been in part to do with the caching and destaging algoithms, the back end disks were certainly starting to become a bottle neck. They were running RAID10 on 15K disks with the spindles doing no other work. May be he could have benefited from SSD on the back end instead of spinning disks?

With disk being so MANY times slower than cache, they often do become a performance limiting factor in a busy environment.

Then again, neither was MTI. However these drives would have been great for hobbiests at home, but not something i would put a production application on. For the most part, I’ll stick to my EMC arrays. They have enough cache in them for any five applications.

Especially since I’m currently working in a mostly windoze shop, there is no chance any dozen Microsquish servers could ever push an EMC array to it’s limit.