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Comment by teovall | Hacker News Reader

This outage is affecting Discord.

https://status.discordapp.com/

Being taken down by slow IO in a single cloud zone seems to implicated their overall architecture.

Looking at their job postings, they use Cassandra and Elasticsearch, so I am somewhat surprised that they didn't survive this outage. (I have not ever run Cassandra at scale, but their website says in the first paragraph that it's designed to handle regional failures.)

If I were on GCP and had paying customers, I would use Cloud Spanner. It's expensive, but it's a good piece of technology.

Most startup companies worry about building out features than building out reliable infrastructure. Almost always an after thought

The gift of Spanner is it’s always slow, so if you start there you will naturally gain experience in either hiding latency or relaxing consistency requirements, which are both good skills.

Spanner is pretty fast, but as with any database you have to use it correctly to get the speed. Since it’s a non-standard database, it requires non-standard tricks and skills.

No, that's about right. You get one write per second per entity or something like that and that's as fast as it goes.

The key is to choose your entity wiseley. I wrote an app inside Google that did on the order of 10,000 writes per second and it was no problem; each entity group only showed up once every minute or so.

AFAIR, entity group is a Megastore concept. Megastore is ill-conceived predecessor of Spanner, are you confusing them? Spanner is much faster than 1 transaction per tablet.

I have run Cassandra in production. A replication factor 3 cluster over 3 AZs should be able to survive loss of a single AZ.

However, it has been my personal experience that Cassandra handles instances going down much better than it handles instances getting very slow but staying online. In that case Cassandra will work extra hard to just spin its wheels. If you know that is what is happening you can be better off manually bringing those nodes offline.

Discord seems to be preventing new connections.

We use Discord as an interface for moderating our app and monitoring spam/reported content so this kinda sucks. Not super important though.

Is it just me or are Discord's status updates legendarily bad to the point of being entirely useless? As a user of the discord app, don't tell me the "API is having issues." Just tell me, "Discord is currently down. We are working on it and apologise for the disruption." Everything else is unnecessary line noise.

Mentioning the cause of the issue seems better than just "shits broke yo" to me.

Really? What in their status update read to you as "the problem is on our side, not yours"? Understand that I'm a programmer and couldn't figure that out.

Because if it was a problem on your end, it wouldn't be listed on their status page....?

"Google's Engineering team continues to work on mitigating the issue"

I think that's pretty clear where the issue lies

The Discordapp status page is written to by developers, and as a developer I really like the insights as to what is going on. As a user, I expect you to just look at it and see it's "Having Issues, We are working on it".

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