-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Shawn,
On 10/11/18 12:54 AM, Shawn Heisey wrote: > On 10/10/2018 10:08 PM, Sourav Moitra wrote: >> We have a Solr server with 8gb of memory. We are using solr in >> cloud mode, solr version is 7.5, Java version is Oracle Java 9 >> and settings for Xmx and Xms value is 2g but we are observing >> that the RAM getting used to 98% when doing indexing. >> >> How can I ensure that SolrCloud doesn't use more than N GB of >> memory ? > > Where precisely are you seeing the 98% usage? It is completely > normal for a modern operating system to report that almost all the > system memory is in use, at least after the system has been > shuffling a lot of data. All modern operating systems will use > memory that has not been specifically allocated to programs for > disk caching purposes, and system information tools will generally > indicate that this memory is in use, even though it can be > instantly claimed by any program that requests it. > > https://en.wikipedia.org/wiki/Page_cache > > If you tell a Java program that it is limited to a 2GB heap, then > that program will never use more than 2GB, plus a little extra for > the java runtime itself. I cannot give you an exact figure for > that little bit extra. But every bit of data on disk that Solr > accesses will end up (at least temporarily) in the operating > system's disk cache -- using that unallocated memory. > > https://wiki.apache.org/solr/SolrPerformanceProblems#RAM To be fair, the JVM can use *much more* memory than you have specified for your Java heap. It's just that the Java heap itself wont exceed those values. The JVM uses quite a bit of native memory which isn't counted in the Java heap. There is only one way I know of to control that, and it's to set a process-limit at the OS level on the amount of memory allowed. I'm not sure how sensitive to those limits the JVM actually is, so attempting to artificially constrain the JVM might end up with a native OOM crash. - -chris -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAlu/YgoACgkQHPApP6U8 pFjcbBAAgYegk20pYvfu3vcrAKxj3s+RSMGRPZ+nN5g0KYQFuhFgptYE+TqjLfBX geekQUNqNUHO5psMA5q/6m6b3LwpqrMxJiapv0wWQ2wPah21CgLs/P/iG+elNQ63 H0ZXbe3wX0P0onZbP4+sfDyzhujZ+5+gMooK87o8Q4z91hIVX1EZfM4lcaZ3pbnb JJ44YorWGPpXjQNEtOHfS7l/Q+8+6+XfEyfKha3JpRFcwcqgLpv23Koy4xgxgYr+ PMqfjptMBMjZ04xSdd491crm2yZowv3KH1Ss8v/L51rknGYPxCEkdKvPrUlpn+Rb 4WnQS6H//dJvQaLum/qR9Jxd+3vc13K7Mn++5Lu+jMbeEgaJU2hD4/ap/KMtFCqn eIXl6HQYPW36sVcm/MIpkRvAgx8vri17sd3/5sOYaETrp4SMxMN5W44GvgDdkbGF R9/tVBCFWb3p+o8eSKUf7QmARiN69DHGVwtQHWMIp8K9893IeHUNgVXKD7281zLB AjHPc7QTvAn4xne0X9lvQjr+YKOPxd9FFqMBejdKht9aBFQvApma9LtJT3FInrob QkSIx594KhoRltRy7E9t3XuWWGg8ujiuzKl6SEPsgXUC2Opwr4Wwu1yn9dCWkFJz RzCKbaDBaNmrK6HSEsoNvS+yQPksPxM8MuchFaCAMZpVOsobCM0= =77dD -----END PGP SIGNATURE-----
