Any time you touch swap you need to consider both overcommit_memory AND overcommit_ratio
The "Ratio" is 50% by default, and the math was counter-intuitive to me... overcommit_memory set to Option 2 tells the kernel it is not permitted to exceed swap + a configurable amount (default is 50%) of physical RAM. So with Swap Set to 8 GB in a 128GB host the math would be... Swap (8GB) + Ram @ 50% (64GB) = 72GB Max Committed by the kernel = bad So disabling swap means.... Ram @ 50% (64GB) = worse! Moral of the story is, either set swap to be at least 50% of RAM or the Kernel will not use commit all the RAM it has with the default configs. For Diskless & Swapless we set overcommit_memory to 2 and overcommit_ratio near 100.
_______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
