The response I've been getting to the Grid Stability Index so far has been very encouraging. The most common request so far has been for an improved scale with better resolution at the low end (some of those high peaks really compress the low end data, and there's a lot more key variation down there.

Accordingly, I've made a few slight adjustments, switching over to a logarithmic scale that should show the data more clearly. I'll be refitting the numbers so far, adding in the new figures alongside the old.

One of the more interesting observations is that while the last twelve months won't win any prizes for stability there are marked and obvious improvements this year, particularly in the last six months. If you look at the graph at the top-right, you'll see one of the most recent ones, where the baseline of three, which had persisted for some time, suddenly dropped as some change made by Linden Lab developers/engineers made a marked improvement in overall stability. There are several notable instances like that, showing gains in stability - however, when the Second Life Grid goes off the rails, it doesn't indulge in half measures.

Today, I'm introducing a new metric, one that I've been working on and refining for some time: The Grid Stability Index (Linden Lab's release of the first of a series of quality-of-service metrics today is entirely coincidental). It's an open-ended scale, starting at zero (stable) and increasing as indicators show variance from a stable situation (including both planned and unplanned outages, service interruptions, login failures, and widespread performance problems).

Yesterday, for example, with downtime and region issues came in at 158.65 [New Scale 22.03]. Complete downtime for a 24 hour period would rate 280, but - considering that amounts to a comparatively stable (if undesirable) situation - there are many issues which could potentially cause the number to exceed that value (the highest recorded is 1,365.94 one year ago on the 19th of September 2006).

In a sense, you can also think of this as a grid instability index, if you prefer. Either way, it gives us a metric for comparison. Just remember, lower numbers are better. We'll bring you today's figure at midnight, SLT (US Pacific).