# ElasticSearch 2.1.1 RAM Issue **URL:** \ **Category:** Elasticsearch\ **Created:** [April 26, 2016, 5:09am UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379 "2016-04-26T05:09:40Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![nkanchas](https://avatars.discourse-cdn.com/v4/letter/n/278dde/32.png) [@nkanchas](https://discuss.elastic.co/u/nkanchas)\ **Post date:** [April 26, 2016, 5:09am UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/1 "2016-04-26T05:09:40Z")
Hi I have strange issue with ES RAM. free -m shows less RAM but KOPF plugin says good free RAM. Unable to figure out how to debug. ES Version = 2.1.1 - Machine has 8 GB RAM alloted ....Java xmx has 4GB configured. ubuntu@vm01:~$ free -m total used free shared buffers cached Mem: 7983 7639 344 0 313 775 -/+ buffers/cache: 6550 1433 Swap: 0 0 0 KOPF Plugin shows heap usage around 4% (Attached same) /\_plugin/kopf/#!/nodes ubuntu@vm01:~$ cat /proc/meminfo MemTotal: 8175564 kB MemFree: 351492 kB Buffers: 321260 kB Cached: 794728 kB SwapCached: 0 kB Active: 1021088 kB Inactive: 346700 kB Active(anon): 274756 kB Inactive(anon): 284 kB Active(file): 746332 kB Inactive(file): 346416 kB Unevictable: 5197136 kB Mlocked: 5197176 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 6488 kB Writeback: 0 kB AnonPages: 5448928 kB Mapped: 46232 kB Shmem: 360 kB Slab: 1186336 kB SReclaimable: 1172644 kB SUnreclaim: 13692 kB KernelStack: 1744 kB PageTables: 15824 kB NFS\_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 4087780 kB Committed\_AS: 5433540 kB VmallocTotal: 34359738367 kB VmallocUsed: 14868 kB VmallocChunk: 34359719707 kB HardwareCorrupted: 0 kB AnonHugePages: 5285888 kB HugePages\_Total: 0 HugePages\_Free: 0 HugePages\_Rsvd: 0 HugePages\_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 30720 kB DirectMap2M: 8488960 kB Help would be appreciated. Thanks, Naresh. ![](https://us1.discourse-cdn.com/elastic/original/2X/4/47475a47db0bf56c5c5ac6aa36c25547bfd5277c.png) ---
**Author:** ![danielmitterdorfer](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/danielmitterdorfer/32/110510_2.png) [@danielmitterdorfer](https://discuss.elastic.co/u/danielmitterdorfer)\ **Post date:** [May 2, 2016, 12:55pm UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/2 "2016-05-02T12:55:28Z")
Hi, I fear I don't understand what are you trying to achieve. `free` shows system-wide memory usage whereas the Kopf plugin only shows Java heap usage of the Elasticsearch process. First, Elasticsearch stores all kinds of things off-heap (in the OS filesystem cache) which you will simply not see in Kopf and second your operating system and other processes will also need memory. I hope this points you in the right direction. Daniel ---
**Author:** ![nkanchas](https://avatars.discourse-cdn.com/v4/letter/n/278dde/32.png) [@nkanchas](https://discuss.elastic.co/u/nkanchas)\ **Post date:** [May 3, 2016, 8:36am UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/3 "2016-05-03T08:36:19Z")
Hi Daniel, Thanks a lot. Then my concern is off-heap memory consumed by ES. Total I have 8GB on box. Java Heap 4GB allotted (this is pretty much fine) Ubuntu OS + ES Off Heap = 4GB (This is where I get problem) How to address this problem? How to know how much off heap ES is consuming ? What is the best configuration of ES to have better off heap usage ? Your inputs helps a lot. Thanks again. **I have below configuration from elasticsearch.yml** bootstrap.mlockall: true action.disable\_delete\_all\_indices: true gateway.expected\_nodes: 1 index.routing.allocation.disable\_allocation: false indices.fielddata.cache.size: 40% network.bind\_host: 0.0.0.0 network.publish\_host: _non\_loopback:ipv4_ node.data: true node.master: true ---
**Author:** ![danielmitterdorfer](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/danielmitterdorfer/32/110510_2.png) [@danielmitterdorfer](https://discuss.elastic.co/u/danielmitterdorfer)\ **Post date:** [May 3, 2016, 1:50pm UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/4 "2016-05-03T13:50:31Z")
Hi, well, all of that looks quite ok: The "Cached" output is the OS page cache, which indicates that just around 800MB are in use. You cannot really attribute that to a single process but I think it is still reasonable to say that most of that is used by ES. By the way, the page cache is entirely managed by the OS. It decides when entries need to be evicted, so there is no setting in Elasticsearch which you can tune. Also on OS level, it is not easily / directly changeable. "Mlocked" indicates the amount of (Heap) memory that ES has locked (i.e. preventing the OS to swap it out). It's more than 4GB, maybe the JVM is allocating also some space in addition what is set by -Xmx. It's also possible that other processes mlock memory (as meminfo just provides a system-global view). "Slab" is Kernel reserved memory and a little bit over 1GB. Let us do a quick back of the envelope calculation: the three before-mentioned parts together account for roughly 800MB + 5GB + 1GB = 6.8GB. You have 350MB free, leaving around 800 - 900 MB for all the rest of the system, which is not too much. You _can_ try to reduce the heap size or allocate more memory to the machine. Off-heap memory usage is definitely not your problem here. I hope that helps. Daniel ---
**Author:** ![nkanchas](https://avatars.discourse-cdn.com/v4/letter/n/278dde/32.png) [@nkanchas](https://discuss.elastic.co/u/nkanchas)\ **Post date:** [May 3, 2016, 4:03pm UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/5 "2016-05-03T16:03:43Z")
> [@nkanchas](#): > > 794 Thanks a lot for details explanation. Reduce heap size worked. I have below setup ES Client Node ( is front facing. All requests read/write goes to Client Node) ES Data Nodes (3) ( no outside interaction. Only client talks to data nodes) I guess with this kind of setup ES Client Node might need more RAM than Data Nodes. Thanks again. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 5, 2017, 10:54pm UTC](https://discuss.elastic.co/t/elasticsearch-2-1-1-ram-issue/48379/6 "2017-07-05T22:54:21Z")