The Internet is abuzz with talk about solid state reliability right now (see a recent article by Jeff Atwood). Random, catastrophic failures aside, how can you know how much life you’ve eaten into your SSD?
If you’ve an Intel SSD, it’s pretty easy; they export a S.M.A.R.T. attribute “Media Wearout Indicator”. Starting at 100 (new), the attribute decreases to, well, zero. Forget how to do that on Linux? It’s easy:
$ sudo smartctl -a /dev/sda | grep Media_Wearout_Indicator 233 Media_Wearout_Indicator 0x0032 098 098 000 Old_age Always - 0
The SSD in my laptop is at 98, and my oldest SSD in another system (from mid-2009) is at 97. Yours?
On to the real news: the OpenStreetMap project has switched their tile rendering server to an SSD (hopefully making tile renders much, much faster). A newer, consumer-grade MLC-based Intel 320 Series 600 GB SSD, in fact. Conveniently, OpenStreetMap monitors their servers with Munin, which by default graphs all S.M.A.R.T. attributes, including Media Wearout Indicator.
Other than the initial import of the tile rendering database, OSM tile rendering does not consume many write cycles. But it definitely hammers the disk to death on reads. Keep a lookout on these graphs to see how their SSD ages over time. Don’t forget to contribute to OpenStreetMap yourself so we can see that number go down a bit quicker (I’m pretty sure OSM doesn’t mind!).
Note: Toby mentioned to me that all the values appear to be pegged at 100. Most of these attributes are dummy values—only “Media Wearout Indicator” and “Available Reserved Space” appear to change with normal use.