DAOS and Transaction Logs

When you want to use DAOS in Domino 8.5.x you need to activate Transaction logging. DAOS allows to store attachments on cheaper disks and eliminate duplicates (Not sure if you want DAOS, use the estimator, it will tell you). BUT DAOS requires transaction logging. Transaction logging requires, to be performant, its own disk. The best practices guide states it very clearly: " It is absolutely essential to place the transaction log directory on a separate physical device devoted solely to transaction logging. Part of the performance improvement you will gain from transaction logging depends on having a separate disk, which allows fast writes to the transaction log files. Putting the transaction log on the same drive as other files — the operating system, the Domino executables, the Domino data, the OS pagefile, etc. — can result in a significant performance degradation even in comparison with an R4 server, since the server must read from and write to these files as well.".

So speak after me:" I shall use a dedicated drive for my Domino transaction log. I won't use a partition, a directory or a SAN destination. I shall use something insanely fast for this drive.".

No ifs or buts or eventuals. So the DAOS savings require some disk investment. While you are on it: make sure you use ODS51 and compression for design and data - and review the design for high performant Domino servers (Raid 10 works best). Others have recommendations too.