What use is SLA? If a service goes down for too long, are you really going to hire a lawyer sue it over SLA or just... use another backup?
For example, my team has people across the world for HW bringup, so we can't allow our code hosting or CI to be down for more than a few hours. Of course, backups have different uptime requirements, but as for everything, it's a tradeoff between features, of which an SLA is one.
Tarsnap's features are granularity of cost, reliability of storage, and encryption, but not 99.999% uptime.
SLI - Service Level Indicators - Metrics ie Latency of each request / response cycle
SLO - Service Level Objective - What threshold we are aiming for - 10 ms from request to response averaged over 1 hour period.
SLA - SL agreement - contract with custom yet what happens if we breach (credits given, put the CTO in stocks and throw eggs at him etc)
Instead we get refunded some pitiful amount when our business is seriously disrupted for an extended period of time.
My youngest once found some sort of chocolate drops called "unicorn poo" - which seems a more ironic thing to chuck at CTOs !
Secure
Technology
Oversight for
Corporate
Software
STOCS Act here we come !
Edit : yeah I could not get the K in ... that's hard
Meeeeh, my ISP cut of around 100+ fiber connections in my town and spend three weeks fixing it. My neighbor have business line, there's an SLA on those that among other things, require them if reestablish his connection within 3 - 5 hours. It took them over 500 hours, so that SLA is useless for anything but forcing compensations.
The problem is that the SLA should give an indication of available resources, but in reality it's mostly a contractual thing for most companies, they'll pay the "fine" or refund a customer if they fail to hit their SLA and that's about it. Tarsnap most likely have better availability than many midsize competitors simply because it's just one person who really cares about it. Doesn't help if he's hit by a bus though.