# Memory usage on startup (old gen full)

**URL:** <https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710>\
**Category:** Elasticsearch\
**Created:** [June 2, 2016, 1:58pm UTC](https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710 "2016-06-02T13:58:10Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![knights](https://avatars.discourse-cdn.com/v4/letter/k/7c8e57/32.png) [@knights](https://discuss.elastic.co/u/knights)\
**Post date:** [June 2, 2016, 1:58pm UTC](https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710/1 "2016-06-02T13:58:10Z")

</div>

Hello, everyone

I am facing a problem with my ES cluster, version 1.7.3  
I have 10 nodes, each having 30g RAM.  
Scatered around thos nodes are 2480 shards.

When I start the cluster, the heap usage skyrocket to 27-29g, with absolutely no cache being used. I'm not doing any indexing, nor do I search or aggregate on my data.  
When I look at my nodes's stats, I can see that the old gen memory uses more than 28g.

If I start indexing, my cluster ends up collapsing due to increased time doing garbage collections that do not free any memory anyway.

I do not understand why I use so much memory.  
Any insight would be greatly appreciated.

PS: please, be patient with my approximative english.

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [June 3, 2016, 2:36am UTC](https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710/2 "2016-06-03T02:36:58Z")

</div>

You should really upgrade to the latest 1.7 release.

How much data in your cluster?

---

<div class="post-metadata">

**Author:** ![knights](https://avatars.discourse-cdn.com/v4/letter/k/7c8e57/32.png) [@knights](https://discuss.elastic.co/u/knights)\
**Post date:** [June 3, 2016, 7:03am UTC](https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710/3 "2016-06-03T07:03:20Z")

</div>

Hello, and thanks for the answer

And yes .. I know I should upgrade, but frankly, If I had any say in the matter, I'd upgrade all the way to 2.3.

Anyway, I have news .. the memory usage plummeted to nice and good level after a while doing absolutely nothing on the cluster.

Since my nodes are running on virtual servers, and since one of the physical server crashed during some heavy indexation(making us lose a bunch of our nodes all at once), I suppose that a lot of memory was used on startup to get back to a stable state. (for the translog files or whatnot)

So the issue seems to have solved itself.  
Anyway, thank again !

---

<div class="post-metadata">

**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, 10:46pm UTC](https://discuss.elastic.co/t/memory-usage-on-startup-old-gen-full/51710/4 "2017-07-05T22:46:33Z")

</div>