Should I generally prefer to run 64-bit database engines on 64-bit Windows?

[VolkerBarth]

I'm about to move a few v12.0.1 database servers from 32-bit Windows Server machines to 64-bit Windows Server 2012 R2 systems.

Given the fact those databases are rather small (3 GB or smaller) and have run sufficiently fast with 32-bit caches (no /3GB boot option set, no AWE-cache, so at maximum 1.8 GB caches), I'm wondering whether to run SQL Anywhere as 32-bit or 64-bit engine.

As all applications are still 32-bit and 32-bit SQL Anywhere engines are linked as LARGEADDRESSAWARE (allowing to make use of a full 4 GB address space under 64-bit Windows, so allowing a doubled cache size compared to the current situation), I would currently tend to stay with 32-bit engines.

Q: Is there a compelling reason to use the 64-bit SQL Anywhere version on 64-bit hardware in such cases - or generally?

(Yes, I know, an actual test would tell more, but I'm asking for a general recommendation.)

[Breck_Carter · Accepted solution]

I vote "yes"... when in Rome do as the Romans do.

[VolkerBarth · Accepted solution]

My own (limited) tests reveal that for smaller loads (i.e. those not making use of caches larger than 3 GB), 32-bit database servers under 64-bit Windows may perform somewhat better, nevertheless the differences are small.

But I had asked for a general rule, and so I'll take your advice:)

[Former Member · Accepted solution]

There's probably no compelling reason not to either.

Given that:

1. the client app's bit-ness is independent to that of the database servers,
2. plus newer hardware is mostly 64bit capable these days,
3. plus (I suspect) the newer compilers are not focusing optimizer improvements for 32bit binaries as much as they will be for the newer generations of 64-bit capable targets
4. ... not to mention in-silicon optimizations that are happening

I would suggest that riding the 64bit wave is looking better all the time.

But that is just some random opinion ...
{your mileage will likely vary}