MaxDB on Windows: Allocation Unit Size for Data- and Log-Files

[stephan_romanith]

Hello everybody,

the SAP notes

1173395 - FAQ: MaxDB Konfiguration

993848 - Direct I/O Mount Optionen für liveCache/MaxDB

talk about different Storage-Vendors and mount-options for Linux/Unix.

But does anybody know if there are special recommandations on Windows for the NTFS Allocation Unit Size for the MaxDB-Data and Log-Files?

Thank you!

Rossi

[lbreddemann · Accepted solution]

Hi Rossi,

no for Windows there aren't any special recommendations, you may well just stay with the NTFS default cluster size of 4K.

In the worst case scenario this means that for a single 8K access two physical IO operations would be necessary.

But in fact, most often the data volume files are allocated in a few rather large contiguous chunks in the file system.

Therefore don't bother with that!

Nevertheless, under certain conditions it might become an advantage to use a 8K cluster size for the file system where you put the data volume files to.

E.g. if you're using a BI system with MaxDB and therefore using the clustering feature a lot.

But until now (approx. 6 years at MaxDB support) I never came across a single case where the cluster size for the NTFS file system would have been the root cause for problems.

regards,

Lars

[stephan_romanith]

Hey Lars,

thank you very much for your answer!

Regards, Rossi