Virtustream Blog

Five “Gotchas” When Migrating to HANA

in Business, Cloud, Technology


By Jake Echanove, Director, Systems Engineering - Americas, @JakeEchanove

One of my C-level execs shot me a short email the other day:


In your experience, what are the five most common 'gotchas' that a customer should prepare for when migrating to HANA and the business suite?

And how do we help them with these?

I wrote the following response in about 10 minutes.

  • Sizing - Many customers have found it easy to add additional disks for their Oracle, DB2 or MSSQL databases (DBs). Adding disks gets expensive when moving to in-mem with HANA, and RAM is much more expensive than disk. This is why accurate sizing is important.
  • Maintenance, housekeeping, and archiving – This goes back to sizing, but there are plenty of basis tables that can be "cleaned" prior to migration to decrease the memory footprint. Most customers don't bother to archive and have a lot of historical data that is never accessed. This is often an afterthought with disk-based DBs. InfoArchive as a Service can help with this.
    • Business value - It’s important for customers to understand the business value of going to HANA. This isn't a magic bullet and custom code often needs to be reworked to take full advantage of HANA. That's because the processing is pushed from the app server to the DB with HANA. In some cases, programs may need to be rewritten to take advantage of this.
    • Underlying application problems - This is where we emphasize the value of a Proof of Concept (PoC). Customers should outline specific, expected outcomes. They should take baseline measurements of existing, long running jobs and do an analysis of where they expect improvement after going to HANA. It’s important to do a lift and shift to cloud before the HANA migration, and then conduct performance testing. This will ensure the customer realizes that moving to the Virtustream platform will be as good and will likely perform better than their current environment. Then, we migrate to HANA and perform the same tests.  For example, with one of our enterprise customers, we did a lift and shift of their DB2 environment and noticed a 20 percent increase in performance. We then migrated to HANA and documented a 10 percent increase in performance from their on-premises environment. The reason for the performance difference was that they needed to do application work before taking advantage of HANA.
    • Support - Most companies will not have the in-house expertise to troubleshoot and manage HANA. If it is their first experience with HANA then they will rely on their Service Provider's expertise as HANA is quite different than traditional DBs and having the expertise to identify performance and functional issues may be lost on the legacy basis team. At Virtustream, we have experience and extensive knowledge on a variety of HANA specific problems, and our customers rely on us to provide expert guidance.