Just a slightly off-topic heads-up - if you use PFS (like pfs3aio for example), the default 30 translates to 150.
http://eab.abime.net/showpost.php?p=1227879&postcount=205
Hard to say what you're going to get with any file system if you use the AddBuffers command or change the number of buffers in the partition data or the mount file
That 150 may be the new 30 is probably misleading to some degree: what quantity exactly is being scaled?
The AmigaDOS documentation is unclear about the effects of increasing the number of buffers, but it suggests that more buffers will increase speed by reducing disk access time (who knew?). The thick binder which came with the Amiga 3000 even mentions the magic word "cache" and explains that each single buffer added will consume about 500 bytes of free memory (could it be 512, and why?).
Because the Amiga file system does not use the buffers primarily as a cache (more like "accidentally"), and adding more buffers can improve performance, there's a different reason for it.
The buffers are statically allocated memory which the file system uses for temporary storage, such as when reading and writing blocks, and the associated low level metadata structures associated with these blocks. Because the buffers are preallocated, the file system is unlikely to run out of dynamically allocated memory when doing its job.
It will, however, run out of buffers if too many files/locks are active or disk access operations (e.g. updating the root directory block or the bitmap blocks) are in progress at the same time. At that point new operations will be delayed until one of the of the older operations finishes and releases the buffers it had claimed.
So any speedup that can be observed, other than the odd cached block that is reused instead of reread from disk, is likely the result of multiple operations waiting their turn until the buffer they need becomes available: more buffers will translate into fewer delays.
