I would like to know that, too.
I know that the buffalo-systems are... well... not very good, to say the least.
I have decided for a Synology DS-413j with 2x500GB for that reason. After upgrading the Synology to 4x500GB, then to 4x1TB and then to 4x3TB, I had 2 sets of HD's uselessly sitting in the drawer. So I went for some cheap 4bay-systems to reactivate these HDs.
I startet with a VERY by intel SS4000e, which could only handle the 4x500GB with VEEEEEERY slow speed, and got my hands on a HS-DHTGL/R5, which ran happily with the 4x1TB so far.
Now I'm again running out of space and decided to upgrade the synology to 4x6TB WD RED and to move the 4x3TB Seagate NAS ST3000VM001 to the Terastation.
I tried one of the HDs for testing and the Terastation recognizes it as 2TB only.
So, anyone got more than 2TB running?
I read some hints about non-official-firmware-builds, but could not find any information if that would allow bigger drives (e.g. if it's worth the hassle).
I am of course searching for a cheap synology or qnap as replacement, but the 6TB-HDs already cost a fortune and I really can't spend any significant amount of money on a NAS-System, so I'm willing to fiddle around with whatever can make use of the 3TB-Seagates