On Aug 25, 2013, at 1:41 PM, Furkan KAMACI wrote: > Sometimes Physical Memory usage of Solr is over %99 and this may cause > problems. Do you run such kind of a command periodically: > > sudo sh -c "sync; echo 3 > /proc/sys/vm/drop_caches" > > to force dropping caches of machine that Solr runs at and avoid problems?
This is a terrible idea. The OS automatically manages the file buffers. When they are all used, that is a good thing, because it reduced disk IO. After this, no files will be cached in RAM. Every single read from a file will have to go to disk. This will cause very slow performance until the files are recached. Recently, I did exactly the opposite to improve performance in our Solr installation. Before starting the Solr process, a script reads every file in the index so that it will already be in file buffers. This avoids several minutes of high disk IO and slow performance after startup. wunder Search Guy, Chegg.com
