*The following is a guest post by Michael Jack, Global Sales Director at Datadobi.
Over the past 13 years, EMC Centera has – and continues to be – the most reliable object storage and compliant archiving platform in the industry. While EMC continues to sell and support Centera, customers are also looking at migration strategies to gain new cloud scale features and automation services.
That’s where Datadobi can help. Datadobi is an EMC Technology Connect business partner that offers DobiMiner, our migration software that migrates Centera customers to other storage platforms. In this blog, we’ll discuss Datadobi’s unparalleled migration experience, and we’ll share considerations and strategies on how to migrate Centera data to EMC Elastic Cloud Storage (ECS).
Centera is one of the most stable platforms in EMC’s storage platform portfolio providing 6 nines of availability. It also has an excellent feature set including the coveted Compliance Edition Plus model used by financial institutions around the world to ensure the immutability of their data. Centera created a new paradigm in the storage industry and set the standard for Object Storage that no other vendor has yet to achieve.
While many use cases for Centera remain strong, the move to next generation distributed cloud, mobility, and Big Data applications are driving many Centera customers to take advantage of the next generation object storage. And with many companies having experienced the cost, risk, and time associated with moving from one platform to another, they are rightly asking ‘how do we move all that data without all that pain?’
So how do you move CAS data? Many EMC customers have experience with NAS migrations but have no idea how to move CAS data. To answer that question, let’s take a brief look at how CAS works. CAS data sits in a flat file space without a classic file structure and accessing it requires having the key known as the Content Address or CA on Centera. When an application writes data (a user file) to a Centera, Centera creates a Content Descriptor file (CDF) and places the CA of the user file in the CDF. It then creates a CA for the CDF and passes that to the application, which stores this in its database. When the application needs to retrieve the file again, it passes the CA of the CDF to the Centera, which looks in the CDF to find the CA of the user file. All pretty complex stuff which is what makes Centera such a great product.
To migrate a CAS file to another platform (be it CAS, NAS, RESTful, OpenStack, etc.) you can’t use a tool such as Robocopy because you have to use the CA to locate the file. You can only achieve this by using:
- The application that wrote the data or
- A specialized migration software such as DobiMiner
You may think migrating the data using the application that wrote the data would be the easiest way; however, this is not the case. Applications migrate data by re-reading it from the Centera and then re-writing it to the new platform. Most applications are not designed for high-speed read and write. As a result, migrations done in this way tend to be very lengthy affairs resulting in additional expenses such as professional services and extended support contracts for the old platform.
DobiMiner takes a different approach – it quickly collects the list of data to be migrated directly from the Centera by parsing the CDFs information to the DobiMiner instance. Because the CDFs contain the CA of the user file and the file sizes the entire scope of the migration is completely understood. This allows the migration team to make informed decisions and have a predictable finish date before actually migrating the data. Once the scope is agreed, the data can be rapidly pumped to the new platform at Terabytes a day.
Once the data has been copied to the new platform, DobiMiner reads back each individual file and compares it with the same file on the old platform to validate its authenticity before declaring it fully migrated.
Mining all the CDFs also enables you to have a complete understanding of your data before migrating. For example, you’ll know whether the data is still recognized by the application, has the data expired but not been deleted, and are the replicated environments in sync? All this information enables you to migrate only the data (and all the data) with true business value ensuring the best ROI on the target platform.
CAS-to-non-CAS – a slightly different kettle of fish
Where all of the above relates to both CAS-to-CAS migrations (such as Centera-to-Centera and Centera-to-ECS) and CAS-to-non-CAS migrations (such as Centera-to-NAS or a RESTful interface), moving data from a CAS to a non-CAS platform can involve additional complexity.
Applications write data to a Centera in one of two ways:
- Through a file-system gateway or
- Natively through the Centera API
Some applications use a file-system gateway (such as the Centera Universal Archive) to write the data to the Centera and it is the file-system gateway that stores the CAs not the application. The application database stores a file path making migrating that data to a non-CAS platform straightforward. The file path known to the application can be duplicated on the new platform making the migration transparent to the application.
On the other hand, applications using the API store the list of CAs in their database and therefore require an additional step in the migration process. Firstly, a file path naming scheme must be agreed for the new platform. A combination of fields in the CDF can be used for this or DobiMiner can create a path itself. Secondly, the list of CAs in the application database must be replaced with the new file path so that the application can access the files after the migration. This database update can occur in one of a number of ways:
- Fully automated – the migration software automatically connects to the application database and overwrites the CA with the new file path.
- Handshake – the migration software creates a file that maps the old CA to the new file path and this mapping is manually used by the application vendor to update the application database.
Unfortunately, some application vendors do not allow either method and only allow migrations through the application itself (making for a lengthy migration).
In conclusion, migrating Centera to another platform can seem like a pretty daunting process – it really isn’t. With DobiMiner, most of the difficult tasks are automated to ensure a simple, low risk, predictable, and fast migration.
Avoid the pain. Take advantage of Datadobi and our partners’ expertise to perform your next migration and let your team focus on your business.