Solve problems caused by Linux Buffer/cache consuming too much memory

At work received a DBA to report a server run some large data, the server can not connect remotely, error, grabbed the log called Dell Engineer detection is no problem, the system has been re-installed,

Now some of the larger data will be reported as the error, because the server is far away from the city IDC room, SSH can not log in, so use the Idrac remote management card to connect to the machine, through the console connected to the server, see such as Error:

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1, memory consumption: DD process kernel will use a lot of memory as disk data cache, due to write 8.5T;
2, from the device, the memory is mainly consumed in the buff:
3, DD If=/dev/zero of=/data$i/test bs=1m count=9000000 Conv=fdatasync &
Parameters Fdatasync Effect: 1) Ensure data refresh to disk, 2) does not brush the file metadata to disk;
as a result of characteristic 2, the buff occupies a surge;

For specific reference: http://www.2cto.com/os/201205/131568.html

4, through the echo 3 >/proc/sys/vm/drop_caches, you can empty Buff/cache, currently this device memory has been restored to normal;


sar-r-f/var/log/sa/sa17

memory usage spikes. Typically, this is due to business procedures.

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Solve problems caused by Linux Buffer/cache consuming too much memory