# Elasticsearch 2,x and Linux kernel versions tested
**URL:** https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756
**Category:** Elasticsearch
**Created:** [January 8, 2016, 8:02pm UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756 "2016-01-08T20:02:04Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Phil\_Scala](https://discuss.elastic.co/u/Phil_Scala)
#### Post date: [January 8, 2016, 8:02pm UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756/1 "2016-01-08T20:02:04Z")
[https://www.elastic.co/blog/key-point-to-be-aware-of-when-upgrading-from-elasticsearch-1-to-2](https://www.elastic.co/blog/key-point-to-be-aware-of-when-upgrading-from-elasticsearch-1-to-2) has the following statement:
- Ensure your kernel version is current, as older releases have issues with the newer fsync used by Elasticsearch 2.x.
it refers to a discussion [Elasticsearch crashes after update to 2.0](https://discuss.elastic.co/t/elasticsearch-crashes-after-update-to-2-0/33437/5).
No where can I find something concrete to tell me what kernels were tested, I realize my Kernel is out of date (2.6) and so I may run into similar issues as the poster in the discussion.
So my question is, what is a "current" kernel?
Thanks
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### Author:  [@nik9000](https://discuss.elastic.co/u/nik9000)
#### Post date: [January 8, 2016, 10:08pm UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756/2 "2016-01-08T22:08:00Z")
> [@Phil\_Scala](#):
>
> So my question is, what is a "current" kernel?
Reasonably modern versions of the Linux distros on the [support matrix](https://www.elastic.co/support/matrix) will be safe. Distro maintainers do lots of crazy backporting so its honestly pretty hard to tell what is on what kernel version sometimes.
At a glance the linked issue seems to be actually about GlusterFS. I imagine so long as you stay away from shared filesystems you should be fine. I believe our CI server is publicly [viewable](http://build-us-00.elastic.co/) so you can look at it, but I know that Elasticsearch gets lots of testing on reasonably modern Debian, Ubuntu, Fedora, RHEL, OEL, Windows, and OSX.
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### Author:  [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [January 8, 2016, 10:09pm UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756/3 "2016-01-08T22:09:21Z")
The current kernel depends on your Linux distribution. You can check the kernel version with `uname --kernel-release`
There were bugs with the journal block device layer (jbd2) and ext3/ext4 in older kernels. You will encounter the issue on spindle disks. If you want to have this fixed on kernel level, you should use Linux kernel \>= 2.6.35 or a patched vendor kernel of \>= 2.6.32. If that is not possible, or you still see the issue discussed, you can modify filesystem mount settings to make journal management more I/O efficient. The `noatime` mount option is important.
Some URLs for reference:
Linux:
[https://bugzilla.kernel.org/show\_bug.cgi?id=42895](https://bugzilla.kernel.org/show_bug.cgi?id=42895)
Red Hat:
[https://bugzilla.redhat.com/show\_bug.cgi?id=735768](https://bugzilla.redhat.com/show_bug.cgi?id=735768)
Ubuntu
[https://bugs.launchpad.net/ubuntu/+source/linux/+bug/607560](https://bugs.launchpad.net/ubuntu/+source/linux/+bug/607560)
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### Author:  [@Phil\_Scala](https://discuss.elastic.co/u/Phil_Scala)
#### Post date: [January 9, 2016, 3:01am UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756/4 "2016-01-09T03:01:26Z")
Thank you both Nick and Jorg, we are currently running CentOS 6.5 (2.6.32-431.29.2.el6.x86\_64 kernel) which fits within the matrix you referenced. We are using SSD's for the data drives without any shared file systems so we could be in OK shape. I will for sure monitor our upgrade to 2.1 and before then do some reading,
Thanks again
Phil
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 5, 2017, 11:25pm UTC](https://discuss.elastic.co/t/elasticsearch-2-x-and-linux-kernel-versions-tested/38756/5 "2017-07-05T23:25:47Z")