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Comment by rythie | Hacker News Reader

Needs updating for SSDs, I'm not sure it's really worth the development time and increased time to market to optimise for rotating disks.

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You seem to have accidentally traveled back in time to 2011 from whatever golden future you live in before posting this comment.

We spent a lot of time over several years tweaking every setting imaginable, trying to get the performance up of a NFS server, none of which really made any difference. Installing SSDs fixed the problem completely. Disk I/O now stays in the single digit percentage range when previously would stay at 100%, sometimes for minutes.

SSDs about twice the price of 15k rpm drives, hardly out of reach for most. Also for VPSs, server axis 20mb unmetered SSDs are cheaper than slicehost's rotating disk based systems. http://serveraxis.com/vps-ssd.php

Yeah, SSDs are going to totally kill 15krpm disks. But killing disks in general is a ways off. In fact, disks might actually be getting cheaper per bit faster than SSDs are.

SSD still costs US$2-US$4 per gigabyte. Spinning rust costs US$0.10-US$0.20 per gigabyte. SSDs are much faster but disks are still twenty times bigger at the same price. A developer hour costs on the order of US$100. If your service uses more than a few gigabytes per developer hour, it's worth some development time to optimize for rotating disks. Whether it's worth increased time to market is harder to calculate.

Thankfully there's a happy fusion of spinning rust and SSD: flashcache [0] and L2ARC/ZIL [1]. Cheaper win.

[0]: https://github.com/facebook/flashcache [1]: http://blogs.sun.com/brendan/entry/test

http://www.facebook.com/notes/facebook-engineering/the-full-...

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