how periodically do you want them? I assumed this some-hours and days snapshots would be sufficient. any particular command with or without grep perhaps? I just had to drop caches, right before your response, the performance was simply too bad. this is for your information, how it was right after dropping and 0+5+25 minutes later https://pastebin.com/LcjKgQkg .. this is what it looks like just after sync; echo 2 > /proc/sys/vm/drop_caches https://pastebin.com/ZCeFCKrb .. 5 minutes later, when performance is starting to get better again https://pastebin.com/8hij8Lid .. 20 minutes after that, you can expect this to consume all the available ram within 1-2 hours 2018-07-16 18:23 GMT+02:00 Michal Hocko : > On Mon 16-07-18 17:53:42, Marinko Catovic wrote: > > I can provide further data now, monitoring vmstat: > > > > https://pastebin.com/j0dMGBe4 .. 1 day later, 600MB/13GB in use, 35GB > free > > https://pastebin.com/N011kYyd .. 1 day later, 300MB/10GB in use, 40GB > free, > > performance becomes even worse > > > > the issue raises up again, I would have to drop caches by now to restore > > normal usage for another day or two. > > > > Afaik there should be no reason at all to not have the buffers/cache fill > > up the entire memory, isn't that true? > > There is to my knowledge almost no O_DIRECT involved, also as mentioned > > before: when dropping caches > > the buffers/cache usage would eat up all RAM within the hour as usual for > > 1-2 days until it starts to go crazy again. > > > > As mentioned, the usage oscillates up and down instead of up until all > RAM > > is consumed. > > > > Please tell me if there is anything else I can do to help investigate > this. > > Do you have periodic /proc/vmstat snapshots I have asked before? > -- > Michal Hocko > SUSE Labs >