It seems no cloud service provider these days is able to offer what was considered an industry standard.
I wonder how many services really had 5 nines availability pre-cloud era either. Somehow I feel your view of it being "industry standard" might be slightly rose tinted
Five nines uptime only exists in the mainframe world. Everywhere else it's a requirement set by someone in management, which is met by the vendor in their marketing material. It's never achieved over the long term, but enough time passes so the inevitable downtime can be blamed on the previous management. The vendor meets their "guarantee" by paying back less than a point on the yearly bill, and then everyone can reset the clock and pretend that it won't happen again.
The only people who suffer consequences are the staff forced to work overtime performing SEV0 RED ALERT theater. They will work through nights/weekends while the responsible parties tut-tut and "manage" by reading updates they can collate into the post crisis report. After that, everyone participates in the joy of emergency meetings to discuss said report that will be entirely worthless when a completely different part of the system fails the next time. A more reliable HA solution will be worked up by the engineers, finance will estimate implementation costs, and it will be turned down by an executive on the 8th hole green because they don't care about anything except improving profitability so they can hand themselves a bonus.
I worked on multiple services since the late nineties on bare metal over multiple datacentres to achieve 5-nines.
With IaaS that is now easier than ever, yet these so-called cloud service providers dont do any of that - they tie themselves to a single AZ and have ZERO redundancy.
its not about AWS/Azure etc. They are providing IaaS. Literally compute services littered around the globe. It is up to these so-called cloud service providers, like heroku, to utilize that infrastructure to achieve 99.999%.
I even gave a link in my comment to what AWS say about this.
Are people downvoting me because they dont read, or what?
You make it sound like AWS has 100% uptime and services built on top of them are completely to blame.
And for something like Heroku's managed DBs you can't just achieve 99.99999% availability on a DB without making certain sacrifices. Availability isn't everything past a certain point
Thats not what im doing at all. I even gave a link to AWS documentation of achieving 5-nines by utilizing multiple AZs, etc. I also reiterated this in the comment you responded to above..
What sacrifices you talking about when synchronously replicating to a backup environment? Write latency? How do you deal with that usually? How much is too much? There are strategies to deal with reducing replication related latency depending on level of consistency required.
Costs and general complexity. It is quite easy to accidentally reduce a system's uptime by introducing extra complexity involved with higher availability
Yeah, I suppose in some circumstances their offering is OK.
I don't think i have ever worked on a system where 10 mins of data loss is anywhere near acceptable though.
I guess for mostly static pages, or self hosting a blog its ok, although id be pissed if i had to rewrite an article. Makes you wonder who their target market is.
Less customers, less moving parts, less to go wrong. I'm sure a lot of places were basically rolling the dice, but I'd imagine a lot won that bet while those that lost it had a much more difficult recovery process than today's vendors.
For non trivial services (in particular ones that need consistency), I'm skeptical that it's realistic to achieve 5-nines at competitive cost. You'll probably achieve it for several years, and then you run into a complex failure which takes 1h to fix, blowing through the downtime budget of a decade.
Their "dynos" are ephemeral. They could literally deploy the images to a backup environment hosted elsewhere.
Their data services could all be synchronously replicated to that backup environment.
And thats it - they dont offer any other core services (and their other services run on the same platform.)
So for (at most) double their infrastructure cost they have another network they can immediately switch over to.
And herokus already soooo expensive. Even if you used a 1-to-1 mapping for ec2 to heroku dynos (which they dont - its multiple dynos per backing instance), you would be looking at 5-10x markup using on-demand instances! Reserved instances are even less expensive. Spot instances can be 5x less again!
I think they could retain their current pricing model and still offer this kind of resiliency - at a minimum.
Fly.io is making strides in this direction, distributing the VMs across multiple availability zones, and routing traffic internally from their multiple geographically distributed POPs - but you need to roll your own DB VMs for multi-az synchronization..
EDIT: seems they do provide managed postgres with synchronized replication now (in beta), neat!
Services providers such as Heroku should be easily able to have five-nines uptime.
They ONLY offer fully managed services, which can be backed by the multi-cloud, multi-AZ setup I refer to - but instead a single product outage from a single upstream provider in a single datacenter is affecting all their clients.
This is a regular occurrence for Heroku - and they charge a substantial premium for their "service".
It's worth noting that the AWS EC2 99.99% SLA is a regional SLA, i.e. it only covers a situation where multiple AZs are down simultaneously.
One AZ going down is not covered by the 99.99% SLA. AFAIK there isn't any per-AZ SLA, only a single-instance SLA of 99.5%. The effective per-AZ SLA is going to be somewhere between the two.
I know they dont, but in the link I gave they tell you how to achieve 5-nines via redundancy - something these cloud service providers (like heroku) neglect to implement.
Comments
Whatever happened to 5-nines uptime? It seems no cloud service provider these days is able to offer what was considered an industry standard.
AWS even have documents telling people how to achieve exactly this! https://docs.aws.amazon.com/wellarchitected/latest/reliabili...
Why don't "premium" service providers like heroku, etc, do this?
I wonder how many services really had 5 nines availability pre-cloud era either. Somehow I feel your view of it being "industry standard" might be slightly rose tinted
Five nines uptime only exists in the mainframe world. Everywhere else it's a requirement set by someone in management, which is met by the vendor in their marketing material. It's never achieved over the long term, but enough time passes so the inevitable downtime can be blamed on the previous management. The vendor meets their "guarantee" by paying back less than a point on the yearly bill, and then everyone can reset the clock and pretend that it won't happen again.
The only people who suffer consequences are the staff forced to work overtime performing SEV0 RED ALERT theater. They will work through nights/weekends while the responsible parties tut-tut and "manage" by reading updates they can collate into the post crisis report. After that, everyone participates in the joy of emergency meetings to discuss said report that will be entirely worthless when a completely different part of the system fails the next time. A more reliable HA solution will be worked up by the engineers, finance will estimate implementation costs, and it will be turned down by an executive on the 8th hole green because they don't care about anything except improving profitability so they can hand themselves a bonus.
Not that I'm bitter or anything.
I worked on multiple services since the late nineties on bare metal over multiple datacentres to achieve 5-nines.
With IaaS that is now easier than ever, yet these so-called cloud service providers dont do any of that - they tie themselves to a single AZ and have ZERO redundancy.
The issue is more like the guarantee is not worth anything.
AWS/Azure/whomever "promise" 5 9s uptime. Something goes wrong, you don't get 5 9s, and what do you get?
A system that went down for 4 hours and a $50 rebate on your next bill!
Your point about the credit s stands, but could providers don't even offer 5 9 SLAs.
E.G. https://aws.amazon.com/compute/sla/
its not about AWS/Azure etc. They are providing IaaS. Literally compute services littered around the globe. It is up to these so-called cloud service providers, like heroku, to utilize that infrastructure to achieve 99.999%.
I even gave a link in my comment to what AWS say about this.
Are people downvoting me because they dont read, or what?
You make it sound like AWS has 100% uptime and services built on top of them are completely to blame.
And for something like Heroku's managed DBs you can't just achieve 99.99999% availability on a DB without making certain sacrifices. Availability isn't everything past a certain point
Thats not what im doing at all. I even gave a link to AWS documentation of achieving 5-nines by utilizing multiple AZs, etc. I also reiterated this in the comment you responded to above..
What sacrifices you talking about when synchronously replicating to a backup environment? Write latency? How do you deal with that usually? How much is too much? There are strategies to deal with reducing replication related latency depending on level of consistency required.
Costs and general complexity. It is quite easy to accidentally reduce a system's uptime by introducing extra complexity involved with higher availability
Oh yeah, there are definitely additional costs and complexity involved.
Im just saying that these cloud service providers offering managed services should be covering all that - they certainly charge as if they do!
And in the case of heroku - and their specific architecture - it is not that complex. Im aware that other cases may vary.
No particular love for Heroku, but you can pay for multi az failover if you want it.
https://devcenter.heroku.com/articles/heroku-postgres-ha
If you don’t pay you won’t get the feature. Given that multi az failover directly impacts their cost that seems pretty fair.
Yeah, I suppose in some circumstances their offering is OK.
I don't think i have ever worked on a system where 10 mins of data loss is anywhere near acceptable though.
I guess for mostly static pages, or self hosting a blog its ok, although id be pissed if i had to rewrite an article. Makes you wonder who their target market is.
has aws ever suffered multi region blackouts? or even all AZs in one?
Less customers, less moving parts, less to go wrong. I'm sure a lot of places were basically rolling the dice, but I'd imagine a lot won that bet while those that lost it had a much more difficult recovery process than today's vendors.
Plenty. But in most cases there was luck involved.
For non trivial services (in particular ones that need consistency), I'm skeptical that it's realistic to achieve 5-nines at competitive cost. You'll probably achieve it for several years, and then you run into a complex failure which takes 1h to fix, blowing through the downtime budget of a decade.
In herokus case:
Their "dynos" are ephemeral. They could literally deploy the images to a backup environment hosted elsewhere. Their data services could all be synchronously replicated to that backup environment. And thats it - they dont offer any other core services (and their other services run on the same platform.)
So for (at most) double their infrastructure cost they have another network they can immediately switch over to.
And herokus already soooo expensive. Even if you used a 1-to-1 mapping for ec2 to heroku dynos (which they dont - its multiple dynos per backing instance), you would be looking at 5-10x markup using on-demand instances! Reserved instances are even less expensive. Spot instances can be 5x less again!
I think they could retain their current pricing model and still offer this kind of resiliency - at a minimum.
Fly.io is making strides in this direction, distributing the VMs across multiple availability zones, and routing traffic internally from their multiple geographically distributed POPs - but you need to roll your own DB VMs for multi-az synchronization..
EDIT: seems they do provide managed postgres with synchronized replication now (in beta), neat!
TBF there is very few real world services that offer customers and non giant size companies 5-nines of uptime.
E.g. my electricity provider doesn't.
Services providers such as Heroku should be easily able to have five-nines uptime.
They ONLY offer fully managed services, which can be backed by the multi-cloud, multi-AZ setup I refer to - but instead a single product outage from a single upstream provider in a single datacenter is affecting all their clients.
This is a regular occurrence for Heroku - and they charge a substantial premium for their "service".
https://floridanewstimes.com/the-decline-of-heroku-infoworld...
AWS doesn't offer 5-nines uptime on Compute.
It's S3 that is 5-nines availability.
AWS's published SLA for Compute (which includes EBS) is 4-nines.
https://aws.amazon.com/compute/sla/
It's worth noting that the AWS EC2 99.99% SLA is a regional SLA, i.e. it only covers a situation where multiple AZs are down simultaneously.
One AZ going down is not covered by the 99.99% SLA. AFAIK there isn't any per-AZ SLA, only a single-instance SLA of 99.5%. The effective per-AZ SLA is going to be somewhere between the two.
Design accordingly. :)
I know they dont, but in the link I gave they tell you how to achieve 5-nines via redundancy - something these cloud service providers (like heroku) neglect to implement.
99.999% uptime still mean around 7 and a half hours of downtime per year.
99.999% uptime is 5m 15s per year: https://uptime.is/99.999
No, just 5 minutes https://uptime.is/99.999
Ups, quick maths == wrong maths.