FAQ – General

01 What is Cloud Postgres?

Cloud Postgres is an automated PostgreSQL cluster creation tool. Cloud Postgres automates the deployment of PostgreSQL 9. Cloud Postgres clusters are:

  • Clustered for failover and performance
  • Optimally sized and performance tuned
  • Tailored to the Open Hosting platform
  • Run with automated backups and event monitoring

The clusters provide for high-availability, improved performance, and disaster recovery on the Open Hosting platform.

02 Why is this so awesome?

Because here-to, configuring, tuning, and deploying PostgreSQL as a two-node cluster with failover, resource monitoring, and automated backups required considerable expertise and time. Cloud Postgres makes this easy and quick.

03 What isn’t Cloud Postgres?

Cloud Postgres is not a managed black-box appliance. Cloud Postgres is also not a database administration tool. Large, active deployments still require human oversight. And, finally, Cloud Postgres is not a massive shared PostgreSQL installation. Simply put, Cloud Postgres deploys to your Open Hosting account full-fledged PostgreSQL clusters running on standard CentOS 6.2, to which you’re given root access.

04 What do you mean by “optimally sized and performance tuned”?

To be precise, Cloud Postgres does two things: (1) it writes the Postgres configuration files to fit the available server memory, and (2) using pgtune, tailors the configuration files based on the expected nature of use – for example, a data warehouse configuration will allocate less memory for connections than a standard deployment. At present, Cloud Postgres doesn’t tune based on actual cluster utilization or the active examination of logs.

05 What do you mean by “tailors deployments to the Open Hosting platform”?

Cloud Postgres was designed to take full advantage of the Open Hosting API and our architecture. Most importantly, the database servers are placed on physically distinct hardware. So, should a host server fail or be rebooted, it will only affect one of the servers in your cluster. In addition, a VLAN securely and efficiently streams the replication service, thereby improving performance and reducing your hosting costs.

06 What do you mean by “automated backups”?

Cloud Postgres can be configured to make full backups and push them by SCP to a remote server. The interval between full backups is a configurable setting. Only the two most recent backups will be retained. In addition, the WAL segments from the oldest backup to the most recent are retained. This will allow for a recovery to any point in time between the oldest backup and the most recent WAL segment. WALs are written and pushed to the backup server at intervals of every 16 MB or 1 hour, whichever occurs first.

07 What events are monitored?

The following events are monitored:

  • Master or standby boot
  • Master or standby heartbeat failure
  • Successful failover
  • Low resources of RAM, disk, or backup disk
  • Backup failure

FAQ – Money

08 What does Cloud Postgres cost?

Nothing. The service is free to use. You are responsible for the hosting costs.

09 Can I try Cloud Postgres for free?

Yes, Open Hosting’s 5-day trials will include resources enough to create a small cluster.

10 I’m not an Open Hosting client, where do I start?

Create a trial account at Open Hosting, which will allow you to create a cluster of two servers, each with 2000 MHz CPU, 1024 MB RAM, and 10 GB disk.

11 Do I pay for the network traffic associated with streaming replication?

You pay the fixed cost of the VLAN, which costs $2/month, or less. Traffic is unmetered.

FAQ – Servers

12 To what version of Linux is my cluster being deployed?

To the Open Hosting pre-install CentOS 6.2 / 64. In the future we’ll offer additional options. And, as with all of Open Hosting’s pre-install images:

  • The VNC password is platform-generated and found near your server.
  • When connecting by VNC, you can login by typing “root” without providing a password.
  • The root user is disabled for SSH and other remote access.
  • For accessing by SSH, use the toor user and enter the VNC password.
  • By default, no swap space is configured on the server.

13 May I deploy to an OS other than CentOS 6.2?

No, not at this time.

FAQ – Networking

14 What network resources are used by Cloud Postgres for a standard deployments?

  • 4 static IPs, one for each server and one for each of the two database roles
  • 2 platform firewalls, one for each server
  • 1 VLAN, for streaming the replication service

15 How are the static IPs allocated?

In total, a Cloud Postgres cluster uses four IP addresses: one for each server and one for each of the two database roles, Master and Standby. Primarily, an application will interact with the cluster via the Master IP. Any and all changes made to the Master are streamed to the Standby across a protected and un-metered VLAN. Optionally, and to improve the overall performance of an application, SELECT queries can be directed to the Standby IP.

16 Do I pay for the network traffic associated with streaming replication?

You pay the fixed cost of the VLAN, which costs $2/month (less with subscription discounts). VLAN traffic is unmetered.

17 How are the Open Hosting platform firewalls configured?

Cloud Postgres deploys each server in the cluster behind an Open Hosting platform firewall. The firewalls have two open TCP ports: 22 and 5432. While the SSH port, 22, isn’t required for the cluster to operate, it is needed for Cloud Postgres to connect with servers during creation and modification. The PostgreSQL port, 5432, isn’t essential for either replication or Cloud Postgres; you may shutdown the server and block the port.

FAQ – PostgreSQL

18 What happens if I edit PostgreSQL configuration files after deployment?

It depends. In the best case, nothing. In the worst case, you break your deployment. But, should you then use Cloud Postgres to modify the cluster, your changes may be overwritten.

19 What happens if I change my root password? Or, remove root or the toor alias?

Your cluster will likely continue to operate without issue. But, Cloud Postgres will prompt you for your root password when next you login.

20 What version of PG is being deployed?

PostgreSQL 9.2

21 Can I break a Cloud Postgres deployment?

Yes, and just as easily as you can break a regular PostgreSQL deployment. With root comes power and responsibility. Use it wisely.

FAQ – PostgreSQL Clustering

22 What types are clustering are supported?

Cloud Postgres supports three clustering options:

  • Master & standby with asynchronous replication: Asynchronous replication treats a transaction as committed once it completes on the Master; the cluster doesn’t wait for the transaction to complete on the Standby. This means the cluster doesn’t ensure cluster-wide consistency. In practice, asynchronous cluster replication is faster because there’s less signaling between servers and less transaction queuing.
  • Master & standby with synchronous replication: Synchronous replication provides for cluster-wide consistency. The cluster only signals the commitment of an INSERT, UPDATE, or DELETE once the transaction has completed on both the Master and Standby. Synchronous replication is advisable for applications that are configured to read from the Standby while writing to the Master, and requiring global consistency.
  • Standalone: Single server, single database.

23 How are the Master and Standby roles allocated?

When running, one server is Master and one is Standby. The first server to come online assumes the role of Master, leaving the other to assume the role of Standby. The servers may trade roles in the event that the Master goes offline or at a user’s request.

24 What purpose does the Standby server provide?

The Standby provides two functions: (1) it waits ready to promote itself to Master should the other database become unreachable, and (2) the Standby is read-ready and able to answer any SELECT queries. An application able to route read-only queries over one or more database connections may enjoy a significant improvement in performance.

25 Is this a managed service?

No. Cloud Postgres is unmanaged. You will be granted root access on the servers in the cluster, which will allow you to manage the server deployments. Managed services can be purchased from one our partners. Open Hosting supports the cloud platform on which Cloud Postgres deploys clusters.

FAQ – Security and Privacy

26 What about security?

Cloud Postgres does not retain credentials to your hosting account or to your individual servers. After logout, your Cloud Postgres session passes out of memory and your account credentials are expunged. Only by providing your Open Hosting UUID and API key is Cloud Postgres able to access your hosting account. Once access is established, Cloud Postgres uses the API to request the default toor user passwords to your Cloud Postgres servers. If the default toor user password is manually changed, Cloud Postgres will no longer be able to access the servers in the cluster without explicitly being past the new password.

27 What about privacy?

Cloud Postgres collects no information about user accounts. Only application event logs are kept, which are used to support and debug Cloud Postgres.

FAQ – Warranty

28 Does Cloud Postgres come with a warranty?

No. Use it at your own risk. That said, please let us know.