I'm Low on RAM! (2)

[alpha754293]

I'm running SuSE Linux Enterprise Server 12 SP1.

Your post "Linux ate my RAM! is MOSTLY true/correct/accurate with a couple of notable exceptions.

But before I get into that - my system specs: Supermicro 6027TR-HTRF 4 dual socket nodes, with each node: 2x Intel Xeon E5-2960 (8-core, 2.9 GHz stock, full load TurboBoost 3.3 GHz, max. TurboBoost 3.6 GHz, HTT disabled) 8x Saumsung 16 GB DDR3-1333 ECC Registered 4R RAM (running at DDR3-800 because it's 4R) 1x Intel 540 Series 1 TB SATA 6 Gbps SSD 1x HGST 3 TB SATA 6 Gbps 7200 rpm HDD

(total memory per node: 128 GB, total memory for the entire system: 512 GB)

Linux caching pagecache and slab objects can have a detrimental impact on application performance because it sees that memory that has been used by pagecache and slab objects = used as you pointed out.

# echo 200 > /proc/sys/vm/vfs_cache_pressure

which is the setting that I am testing right now, after have executed:

# echo 3 > /proc/sys/vm/drop_caches

and on two of the nodes, they're currently caching between 82 GiB to 94 GiB to RAM right now.

So - long story short, that REALLY sucks when you have an application that needs about 73 GiB of RAM to run.