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Release Engineering at Openbravo

Amazon EC2: backup management tips

Cloud Computing services offer a great deal of advantages to end users and sysadmins. I’m sure most of us appreciate not taking care about the hardware, having agility to provision new resources, getting the ability to recover fast from disasters, taking benefit of a very high network bandwidth speed, and so forth. It’s a very good solution for many situations.

However managing a Cloud is different compared to the traditional server management. We have been using Amazon EC2 in Openbravo for the last couple of years, so I would like to share some tips with you with regards to backup management and recovery.

DNS management: Elastic IPs

Making backups is the first step towards a successful system recovery. But in order to take benefit of these backups it is also essential to react in a quick and easy manner when something goes wrong, so that we have the system is back up and running in a matter of minutes.  One of the biggest delays tied to the traditional server management comes with the DNS changes. That is, migrating to a new machine usually means having a new IP address. And therefore it forces you to update the DNS records, and this might take days to propagate.

Amazon has a nice feature called Elastic IP that allows you to forget about this. You basically allocate an IP address for you, so that you can assign it to any of your machines “on the fly”.

Think about the difference:

  1. Traditional DNS management: if a new server gives me a new IP I have to change the DNS records.
  2. Elastic IP DNS management: I can assign my IP address to any of my instances.

The first option might take several days to be spread in the entire world, while the second one is immediate.

EBS: persistent storage

Amazon EC2 has continuously improved the features they offer. One of the limitations it initially had consisted of the fact that the hard drives where not persistent. That is, if you shut down a machine you lose your data. In September 2008 Amazon introduced the EBS hard drives (Elastic Block Storage), which means persistent storage that essentially works like a normal hard drive that you can attach to any of your instances. However you could not run the entire operating system in one of these EBS drivers. In any case this was a big step forward, given that you could save your critical dynamic data (e.g. a database) in a persistent storage. Starting from December 2009 you can finally run an entire operating system in a EBS unit.

This feature is relatively new so most of the public AMIs are still based “instance-store”, instead of in “EBS-store”. The recommendation here is incremental:

  • Make sure you save your critical dynamic data in a EBS drive.
  • If possible, run the entire instance in a EBS drive.

I’ve just said that it works similar to a regular hard drive you can attach to any instance. This is not entirely true, it’s better: you can make snapshots of the entire disk. As many as you want, and they are incremental. You can of course restore them into a new drive any time you want.

So as a last tip with EBS do regular snapshots, and make sure you purge the old ones.

Off-site backups

There’s a golden rule with regards to backups: “Do not put all the eggs in the same basket”. It is very unlikely for Amazon EC2 to suffer a general downtime or disaster so that you would loose your data (e.g. a fire). They make sure this won’t happen and they do their backup homework as well. In any case it is generally a good idea to have a second recovery plan, physically isolated from your main backup location.

Amazon EC2 currently has two independent regions (US and EU), so the first option is to replicate the backups from region to another. However if a malicious user gets your EC2 credentials they might have temptations to wipe out all your data in both regions. To avoid this, as a recommendation, create an extra EC2/S3 account with complete read-only access to the first account. So that your backups cannot be compromised in that way.

If you are more paranoid than this, you can schedule weekly or biweekly backups to an external storage service provider.

Physical backups

It is sometimes very useful to have a recent backup available with you at your office. One option is to download it. But depending on the size of your backups and your network speed this might be prohibitive. Amazon has a nice feature called Import/Export that covers this need:

  • You send a hard drive to them with instructions.
  • They load the requested data into the hard drive.
  • They send you the hard drive back.

Openbravo ERP and EC2

OK, those tips sounds reasonable. So what should I specifically do with my Openbravo ERP instance in EC2? Stay tunned, a new post will be coming soon covering this topic.

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Written by jpabloae

10/03/2010 at 16:11

Posted in openbravo

Tagged with ,

4 Responses

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  1. how to take backup of complete cloud instance on amazon EC2?

    dhanesh mane

    28/02/2011 at 11:32

    • Hi Dhanesh. Starting from the 2.50MP27 and 3.0RC4 Amazon AMIs we have you have make use of the EC2 snapshots capability to easily clone an instance.

      I’m planning to blog about details on how to do this during the next week :)

      jpabloae

      04/03/2011 at 16:01

  2. Hey jpabloae, I am thinking about using a company called n2ws do you have any experience with them?

    • No, I don’t have any experience with them. The article you’ve linked contains a very reasonable strategy, though.

      jpabloae

      11/06/2013 at 15:26


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