Organizations have always had applications requiring the storage of their data and in some cases for that data to be immutable. In the late 1990’s, optical jukeboxes were the state of the art for this type of storage. They replaced tape, thanks to their reliability and speed of access. But these devices were much slower than the primary storage systems of that era and were difficult to manage. In 2002, EMC raised the shipped Centera, a hard disk storage system based on Content Addressable Storage (CAS). It provided more flexible retention and immutability than optical but also delivered better response times thanks to its hard disk foundation.
While Centera served the organizations that selected it well for the past 15-plus years, all things, as they say, must come to an end. The new standard in unstructured data storage is becoming more prevalent: object storage. Systems like EMC’s Elastic Cloud Storage (ECS) offer greater flexibility in hardware configuration, lower overall costs and most importantly a wider variety of protocols that include Content-Addressable Storage (CAS), like Centera, as well as support for all of the major object protocols (S3, Swift and Atmos), as well as both NFS and HDFS. IT can also leverage ECS for far more use cases than Centera.
Centera stores data in very unique ways, which means migrating data from it is not as simple as a drag and drop copy. Also, because of Centera’s success, hundreds of applications were written to talk specifically to its proprietary API. Centera customers who are approaching a tech refresh must either select a storage system that natively supports the CAS API or endure a lengthy and costly application based migration. This, of course, assumes that the application vendor has re-written their application to support the new API. To spare customers from this pain, Dell EMC ensured that ECS includes native support the Centera API. This means that ECS will look like Centera from an application perspective, minimizing tech refresh complexity and impact to operations.
EMC offers two methods for migrating from Centera to ECS. Which you choose will depend largely on the specifics of your environment. The first is Dell EMC ECS Sync. This system copies data from ECS, as well as its metadata dependencies, and transforms the data so it is object storage ready. It can make a baseline copy while the application remains active on Centera. Once it creates the first baseline, a quick sync of the data to change any alterations to the baseline copy creation. The application must either be down or at least in read only mode while performing this final sync.
Like most migration tools, ECS Sync waits until the migration is complete to begin writing new data to ECS, so customers must ensure that they have sufficient available capacity on their Centera to last throughout the migration. The ECS Sync servers are installed on ESX Virtual Machines, which requires the customer to have an external infrastructure, but enables multiple servers to be used for larger migrations. One limitation that ECS Sync should not be used is for customers who are using any of Centera’s Advanced Retention Management features, which include Event Based Retention, Litigation Hold and Min/Max Governor.
The other migration option available is the ECS transformation engine. This tool is incorporated into the ECS code, so there is no external infrastructure required to use it. Migrations that use the ECS Transformation engine are designed to be non-intrusive, and to give the customer with a seamless background migration experience. One critical distinction from other migration tools is the application is pointed to the ECS at the start of the migration, so all new data is written to the ECS. This seamless background process is well suited for some customers, but not ideal for those who have a hard or aggressive timeline to complete the migration or for those who wish to provide their own clip list to use for the migration.
The technical advantages of ECS vs. Centera are significant. ECS is higher performing, supports more protocols and is more cost effective. But one of the charges leveled at Centera was that data can’t be migrated from it. The reality is that data can be easily migrated from the system, in fact the customer has two options available to them, depending on their requirements.