Hacker News Reader

Comment by merb | Hacker News Reader

I wonder if some can run a postgresql database on top of that. This would make it relativly easy to have a master without downtime and be way cheaper than RDS.

View on HN

It claims to present itself as a full filesystem so I don't see why it wouldn't, however, you're probably going to run into pretty hardcore performance issues, because the bandwidth amazon provides in general is on the stingy side, but under a terabyte, they're downright miserly, with a 10 gig filesystem only able to provide 0.5 MB/s sustained. This product is problematic at best.

Also, it is a full-fledged NFS-mounted file system.

I would be very wary of running a database from that.

It sounds like a disaster waiting to happen. The latency of NFS is just too high (Even if it is very fast for NFS) for it to be safe for a database.

We're running Oracle on NFS volumes, and some MySQL databases also with no problems whatsoever.

It'll never be as fast as local disk but the flexibility it provides is very nice.

That's normal NFS. Amazon's offerings, if you have a 10 gigabyte database, you can only get 500KB/sec bandwidth --

http://docs.aws.amazon.com/efs/latest/ug/performance.html

Huh. well that's kinda shitty.

Our NetApp can saturate 10GBe without even trying.

I was more thinking about the risk of locking not working as intended on NFS (http://0pointer.de/blog/projects/locking2. See also the section on Nightmare File System in the UNIX-Haters Handbook (https://en.wikipedia.org/wiki/The_Unix-Haters_Handbook)).

There are workarounds for the stateless mess of NFS in modern linuxes, but if you accidentally access a NFS-mounted database from multiple AWS instances, you might get into big trouble, especially when the machines in question run different OSes (e.g. Windows and Linux) or OS versions.

How exactly is it "without downtime"?

It's essentially NFS, so yes.

Reply on news.ycombinator.com