Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it’s on-topic for Server Fault. Closed 7 months ago. Improve this question Asked this in network-engineering in stack exchange and was redirected here. I have a couple of servers with the below config server1: eno1: … Read more
I’m emerging udev and it complains it couldn’t find the kernel sources under /usr/src/linux (there’s nothing inside /usr/src/ indeed). As a result, it tries to take the version from the currently running kernel and messes up thinking it’s an older version than what it needs (when it actually isn’t). So where are the sources so … Read more
This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 8 years … Read more
This question already has answers here: Can’t resolve issue: iptables: No chain/target/match by that name (3 answers) Closed 6 years ago. I had a CentOS6.7 with OpenVZ. Now, I just uninstalled OpenVZ and start using Plain CentOS6.7. Due to some difficulties for using cPanel in OpenVZ. I noticed one problem when install csf in my … Read more
I am hardening a server and attempting to build a restrictive layer to a potential hacker even with root access to the server to do harm. If a user gains root or user access to the shell via say ssh, is there any other way for a user to access system commands other than via … Read more
I have been updating some servers to the latest patchlevels and wanted to check the security state regarding Meltdown, Spectre and Spectre-NG. Using the current V 0.39+ of the spectre-meltdown-checker I was astonished about my findings in a VM running CentOS 7 with VMWare ESXi 6.5 (all patched up to date). Here I found “vulnerable … Read more
Does someone know, if the underlying hardware supports memory hotplug, in Linux is supported without reboot? Especially in Centos 6.x(x86_64). Thanks Answer It is supported in RHEL 6.x (try to use >6.0) but I would strongly urge you to install all of the drivers from your server vendor first. In HP servers this is easy … Read more
On rhel 7, when transparent hugepages are activated, I get a better stream benchmark performance than when transparent hugepages are off. Do you have any idea of a kernel parameter (or another thing) which could trigger this behavior ? I was expecting to have same stream performance with or without transparent hugepages (like in rhel … Read more
When building an upstream kernel, /boot/vmlinuz and /boot/System.Map are updated to point at the newly installed kernel image. Is it possible to disable this behavior, perhaps by changing a config or Makefile parameter? I’m building the kernel like this: make oldconfig make bzImage make modules make modules_install make install Answer make install calls /sbin/installkernel which … Read more
I have two identical Linux laptops (Core™ i7-4810MQ with 32GB RAM) both running Ubuntu 16.04. Running seemingly any command on machine 2 takes about 4-12 times as long as on machine 1, depending on the activity. This was noticed late last week while running some simple gradle builds and hasn’t changed since then. To measure, … Read more
