So I've read the tuning guide, I've played around with different options for SIZE and NUMBER of buffers and I understand the formula of SIZE * NUMBER * drives *MPX as it relates to shared memory.
Here's my question. Of the four parameters:
MPX level
# of drives (I have 12 drives)
NUMBER of buffers
SIZE of buffers (must be multiple of 1024 and can't exceed the block size supported by your tape or HBA)
The NUMBER of buffers and MPX level seem to be the two variables here. I have MPX set pretty low (2 or 3) and NUMBER of buffers set to either 16 or 32. When I multiply it all out, I get a hit on my shared memory of less than a GB. My media servers are dedicated linux hosts that only function as media servers and that's it. Furthermore, they each have somewhere around 35 - 50 GB of memory a piece.
With my current configuration, I'm not even scratching the surface of the amount of shared memory that's sitting idle in my system while my backups run at night. Is there any reason I shouldn't jack the NUMBER of data buffers up to... say... 500? 1000? I've seen some people mention that they have the number of buffers set to 64, but can we go higher?
I've searched around to see if there's a technote on the upper limit of the NUMBER buffers parameter. If there is such a tech note, I can't find it.
Any ideas?
