§ Networks are now faster than disks

I learnt of this counter-intutive fact first from this usenix article no SQL . On checking up, it seems to actually be true. Jeff Dean's keynote at LADIS 2009 report these numbers:

• Round trip within same datacenter: 500,000 ns
• Disk seek: 10,000,000 ns [regular disk ]

On the other hand, a commentor on this discussion at serverfault mentioned that SSDs might be much faster, and the numbers bear out:

• Read 4K randomly from SSD: 150,000 ns
• Round trip within same datacenter: 500,000 ns
• Disk seek: 10,000,000 ns [regular disk ]