9 ms·

There are a couple of options for making your front-end redundant: round-robin DNS, or a CDN. In either case, it still leaves you with a single point of failur

There are a couple of options for making your front-end redundant: round-robin DNS, or a CDN. In either case, it still leaves you with a single point of failure in the backend. Your best bet there is probably to get a second VPS through a completely different provider -- and figure that you'll never lose both at the same time -- and then set up replication between the two databases, along with a monitoring process to switch the front-end to the backup database in the event that the primary becomes unreachable.

olefoo 17y ago
Round Robin DNS can play havoc with e-commerce software that was built on dumb assumptions about session handling. The usual symptom is carts vanishing and reappearing semi-randomly. If I'm going cheap a webserver set up as a reverse proxy can manage a large number of sessions spread out over multiple application servers. It's not as good as dedicated network hardware, but it's better than round-robin dns.
- thaumaturgy 17y ago
  Ugh, I didn't know that about session handling. As a tangent: guys, current ecommerce packages really, really suck. I've had a couple of ecommerce jobs recently, and for one client in particular, had to evaluate most of the field of both free and commercial offerings. They're almost uniformly horrible. Is there anybody willing to take a crack at doing it better? I suggested round-robin DNS over a reverse proxy because reverse proxies (and similar services, like OpenBGPd) still have a single point of failure in the front-end. No matter what you do, it can still go down, and then all that back-end redundancy does squat.
  - blasdel 17y ago
    http://spreecommerce.com http://spreecommerce.com is the best I could find, I've recently been customizing it for a client.
    - thaumaturgy 17y ago
      Thanks for the link! Looks like I finally have an excuse to learn Ruby.
  - olefoo 17y ago
    The fix in most cases is having a shared session-store (memchached usually) that the front-end instances share. It's not that painful to retrofit it if you know the software.
andrewbadera 17y ago
There are DNS failover providers that will host your DNS records and provide monitoring and automatic failover between IPs. This takes propagation time out of the equation.
- bluebird 17y ago
  Could you please list a couple or recommend one out of experience? Thank you.
- thaumaturgy 17y ago
  This unfortunately doesn't resolve problems with bad caching behavior -- not all internet service providers, including the big ones, are observing TTL or sane caching. I think you're still better off solving the problem without relying on TTL or DNS caching behavior that you don't have control over.

olefoo 17y ago

Round Robin DNS can play havoc with e-commerce software that was built on dumb assumptions about session handling. The usual symptom is carts vanishing and reappearing semi-randomly. If I'm going cheap a webserver set up as a reverse proxy can manage a large number of sessions spread out over multiple application servers. It's not as good as dedicated network hardware, but it's better than round-robin dns.

thaumaturgy 17y ago
Ugh, I didn't know that about session handling. As a tangent: guys, current ecommerce packages really, really suck. I've had a couple of ecommerce jobs recently, and for one client in particular, had to evaluate most of the field of both free and commercial offerings. They're almost uniformly horrible. Is there anybody willing to take a crack at doing it better? I suggested round-robin DNS over a reverse proxy because reverse proxies (and similar services, like OpenBGPd) still have a single point of failure in the front-end. No matter what you do, it can still go down, and then all that back-end redundancy does squat.
- blasdel 17y ago
  http://spreecommerce.com http://spreecommerce.com is the best I could find, I've recently been customizing it for a client.
  - thaumaturgy 17y ago
    Thanks for the link! Looks like I finally have an excuse to learn Ruby.
- olefoo 17y ago
  The fix in most cases is having a shared session-store (memchached usually) that the front-end instances share. It's not that painful to retrofit it if you know the software.

andrewbadera 17y ago

There are DNS failover providers that will host your DNS records and provide monitoring and automatic failover between IPs. This takes propagation time out of the equation.

bluebird 17y ago
Could you please list a couple or recommend one out of experience? Thank you.
thaumaturgy 17y ago
This unfortunately doesn't resolve problems with bad caching behavior -- not all internet service providers, including the big ones, are observing TTL or sane caching. I think you're still better off solving the problem without relying on TTL or DNS caching behavior that you don't have control over.