@pete-s said in Small colo infrastructure for SaaS:

Alright, just to recap.

We have two options here and we could use either option depending on the VM and the application itself.

• Continuous VM replication (VM host to VM host replication?)
• Database replication (VM guest to VM guest replication)

And neither of them would require shared storage.

Is that correct?

That is correct. In either case, nothing is shared.

With the guest replication though, nothing has to be changed. Just turn on the VM on Host B.

With the DB replication, you have a lot of items that may need to be changed.

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

My biggest question is why split workloads, rather than just the two servers, one acting as the active host, the other acting as the backup host.

Remove the NL Storage server entirely.

Perform continuous replication from Host A to Host B, as well as backup offsite.

Why even that much complexity? Only piece that needs replicated normally is the database.

Because you'd need to have a readily available to use infrastructure somewhere that can host said database. Which might be beyond the technical expertise at the table to configure.

It's pretty basic for any database today.

Sure, its easy enough to move a database in a planned move, during a disaster you have to pay the host, setup the DNS records, move the data, let all of the changes sync.

VM replication is extremely straightforward. On XenServer with XO it creates a full initially and then only performs the delta's afterwards.

The data is on both locations, always.

@jaredbusch said in Small colo infrastructure for SaaS:

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

My biggest question is why split workloads, rather than just the two servers, one acting as the active host, the other acting as the backup host.

Remove the NL Storage server entirely.

Perform continuous replication from Host A to Host B, as well as backup offsite.

Why even that much complexity? Only piece that needs replicated normally is the database.

Because VM replication is not added complexity. it is easier, by far, than managing individual databases on every VM.

That's also a very good point.

@pete-s said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

My biggest question is why split workloads, rather than just the two servers, one acting as the active host, the other acting as the backup host.

Remove the NL Storage server entirely.

Perform continuous replication from Host A to Host B, as well as backup offsite.

Why even that much complexity? Only piece that needs replicated normally is the database.

Because you'd need to have a readily available to use infrastructure somewhere that can host said database. Which might be beyond the technical expertise at the table to configure.

I don't want to replicate the db to the cloud. And I want to have the backup locally available - even if I will also backup to offsite at times.

Colo is 30 minute drive from our office.

Well, it will cost more upfront to do, but the solution is still sound. I would recommend an approach like Host A - Master, Host B slave - NLS backup target

Host A performs continuous replications to Host B, as well as Host A backs up to the NLS host on a different schedule.

Should Host A go down, everything is on Host B with a quick startup and you're off to the races.

You'd still have your separate backups to recover from should something even worse occur.

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

My biggest question is why split workloads, rather than just the two servers, one acting as the active host, the other acting as the backup host.

Remove the NL Storage server entirely.

Perform continuous replication from Host A to Host B, as well as backup offsite.

Why even that much complexity? Only piece that needs replicated normally is the database.

Because you'd need to have a readily available to use infrastructure somewhere that can host said database. Which might be beyond the technical expertise at the table to configure.

My biggest question is why split workloads, rather than just the two servers, one acting as the active host, the other acting as the backup host.

Remove the NL Storage server entirely.

Perform continuous replication from Host A to Host B, as well as backup offsite.

@scottalanmiller said in Small colo infrastructure for SaaS:

@pete-s said in Small colo infrastructure for SaaS:

@scottalanmiller said in Small colo infrastructure for SaaS:

In that case, why the live migration? Should not be needed at all, correct? If one node dies, the other just takes over?

Live migration for service, upgrades and such.

When would that be needed? Maybe I'm picturing a very different setup....

Host updates that require a reboot. Few and far inbetween now-a-days.

@pete-s said in Small colo infrastructure for SaaS:

@scottalanmiller said in Small colo infrastructure for SaaS:

In that case, why the live migration? Should not be needed at all, correct? If one node dies, the other just takes over?

Live migration for service, upgrades and such.

This would be in the case of performing host updates only. You're not gaining true HA at the application layer. If the guest takes a dive, you're still recovering from backup.

@scottalanmiller said in Small colo infrastructure for SaaS:

In that case, why the live migration? Should not be needed at all, correct? If one node dies, the other just takes over?

I'm thinking for those cases of a host catching on fire.

@scottalanmiller said in Small colo infrastructure for SaaS:

@dustinb3403 said in Small colo infrastructure for SaaS:

You can even get Near-HA with the pool functionality in XenServer or XCP-NG. Or you can use StarWinds vSAN and have true sHA for little overhead.

For a third party workload, I'd do that. But for a bespoke app, I bet he doesn't need to. You can make it all failover with nothing more than load balancing.

True, but its nothing more than a control function to "move" the workload to another host in the pool.

You can even get Near-HA with the pool functionality in XenServer or XCP-NG. Or you can use StarWinds vSAN and have true sHA for little overhead.