Questions tagged [linux]

Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.

6,615 questions with no upvoted or accepted answers
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9
votes
1answer
2k views

Is it possible to do multiseat the systemd way with one graphic card / two heads?

I would like to setup a multi-seat configuration using Ubuntu Xenial 16.04. After some researches, it seems the way to do now is by systemd through "loginctl" calls. (saw here for example). Before ...
8
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1answer
198 views

Can Samhain monitor for a file that does not exist, but might in future?

I would like Samhain to monitor a file, say for example, /root/somefile. This file does not currently exist, but I would like to be notified if it gets created at any point. I add this to samhainrc: ...
8
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2answers
297 views

what is the IOPS behavior when partitions of single disk are used in an LVM?

I have an ubuntu 14.04.1 LTS server which have LVM(backed by hardware RAID5) with logical volume and a volume group named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from same sdb ...
8
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1answer
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CentOS 6 local update repository and security updates

I know that official CentOS 6 (even 7) update repositories does not provide security information. The consequence is thatyum-plugin-security plugin and yum check-update --security command does not ...
8
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2answers
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information about /proc/pid/sched

Not sure this is the right place for this question, but here goes: I'm trying to make some sense of the /proc/pid/sched and /proc/pid/task/tid/sched files for a highly threaded server process, ...
7
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1answer
5k views

Cannot edit VM or access it via SSH. error:Supplied fingerprint does not match current metadata fingerprint

I have a Linux machine on Google Cloud, created with Bitnami. It was working well, and it could be accessed through SSH, usign the web console or putty. However suddenly today it can not be accessed ...
7
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2answers
549 views

What repository is a yum group sourced from?

Is there an easy way to determine where a specific yum group is sourced? I can query what groups are available using yum grouplist. I can query group information using yum group info $yum_group_name ...
7
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0answers
2k views

ZFS cannot import : I/O error

I experienced an error in my ZFS machine. This may have happend after I lost power to my server, but I can not tell for sure. My ZFS Pool Gewuerzglas with RAIDZ-1 is no longer willing to import. I ...
6
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0answers
929 views

Caching, forwarding Bind 9.9.4 server works for weeks, suddenly SERVFAIL on all queries (rebooting fixes it)

I have bind 9.9.5 running on two servers (CentOS 6 and 7), for caching and forwarding DNS queries for a mail server. The servers run fine for weeks, then suddenly respond to all queries with SERVFAIL. ...
6
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0answers
133 views

Write arbitrary attribute into ENV from LDAP upon successful PAM authentication

Is it possible during the authentication phase of pam_ldap to map an arbitrary LDAP attribute of the user's record into the resulting user's environment? The specifics of my situation, in case you ...
6
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0answers
4k views

Server went offline for no reason except SIGINT?

We had a system go offline this morning. The only thing in syslog is: Mar 20 15:27:15 fooserver systemd[1]: Received SIGINT. Mar 20 15:27:15 fooserver systemd[1]: Starting Synchronise Hardware Clock ...
6
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2answers
702 views

Q: RHEL, SSSD, Active Directory

Good afternoon folks. I've been perusing various posts already about getting linux systems to authenticate using AD, but haven't seen anything approaching what I'm beating my head against. There's a ...
6
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1answer
3k views

What does sunit=0 and swidth=0 mean for XFS file system?

I created an XFS file system using default parameters at the time of creation of a system. Now looking at the output of xfs_info, it show 0 for the values of sunit and swidth. I can't seem to find ...
6
votes
1answer
2k views

SSSD process won't die

Thanks for taking the time to check out my problem. I'm currently working on an issue that has only appeared once before. Back on Jan 3rd when this first appeared we were able to reboot the server ...
6
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2answers
2k views

Not Able to Mount USB HDD in Linux

I'm having a problem with a server that I just installed kernel 2.6.18-371.el5 on. It's an old kernel for Red Hat 5, I know, but due to certain "restrictions" I am forced into using that for the time ...
6
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0answers
1k views

TCP congestion collapse

I am experiencing suboptimal performance on an EC2 instance connecting to an RDS instance. This particular instance was built before VPC's existed, so all the traffic is flowing through a single ...
6
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0answers
16k views

ActiveMQ - “Cannot send, channel has already failed” every 2 seconds?

ActiveMQ 5.7.0 CentOS release 6.3 java version "1.6.0_26" Application server: Tomcat In the activemq.log, I'm seeing this exception every 2 seconds: 2013-11-05 13:00:52,374 | DEBUG | Transport ...
6
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5answers
4k views

Creating a fallback error page for nginx when root directory does not exist

I have set up an any-domain config on my nginx server - to reduce the amount of work needed when I open a new site/domain. This config allows me to simply create a folder in /usr/share/nginx/sites/ ...
6
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1answer
3k views

Linux Client Active Directory Authentication stops working when failover

I have an issue with Linux clients trying to AD authentication by targeting a DNS name (corp.example.com). I have 2 Domain Controller servers DC1(10.0.0.3/24), DC2(10.1.0.3/24) both domain controllers ...
6
votes
1answer
671 views

Intermittent munin-cron error “There is nothing to do here, since there are no nodes with any plugins”

We've installed munin monitoring on one of our servers. Generally it seems to be working well but occasionally, 4 times in 2 months to be exact, munin-cron has generated the following error: [...
5
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0answers
675 views

Samba and AD - “net ads changetrustpw” fails

I've got a Samba member of a Windows AD. I'm using a combination of sssd and winbind. Samba manages machine password changes, and it's configured also to update the passwords used by sssd. (The ...
5
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0answers
2k views

Change default certificate signing algorithm in ssh-keygen

Presently, OpenSSH 7.8 (Fedora 28/Arch) is unable to negotiate with a OpenSSH 7.4 (CentOS 7) server utilizing a certificate signed key, as described in a bug filed on redhat's bugzilla. OpenSSH ...
5
votes
1answer
606 views

How long is an (accepted) ICMP redirect observed for, and how can I shorten that time?

If a Linux host receives and accepts an ICMP redirect (accept_redirects=1 on the interface in question), how long is this route being cached for and observed? Can I lower that time? I am asking ...
5
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1answer
521 views

How to debug failed checksums/flipped bits in TCP packets?

A web application we maintain recently encountered a very weird problem: three out of four virtual machines on two physical hosts had trouble connecting to the server of our payment provider via HTTPS....
5
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1answer
1k views

How do I secure the access token, on Linux, to remote, automated secrets stores like Hashicorp Vault?

There seems to be a bit of a "chicken and egg" problem with the passwords to the password managers like Hashicorp Vault for Linux. While researching this for some Linux servers, someone clever asked, ...
5
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1answer
1k views

mdadm - stuck reshape operation

I have a 3 disk RAID 5 array that I tried to add a 4th disk to. mdadm --add /dev/md6 /dev/sdb1 mdadm --grow --raid-devices=4 /dev/md6 This operation started successfully and proceeded until it hit ...
5
votes
1answer
169 views

Can servers with encrypted root filesystems be made reasonably highly available?

I have some servers I'd like to keep on encrypted disks, but I don't want to have to manually type a passphrase at every boot. I also don't want to keep the key on the machine unencrypted. TPM would ...
5
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0answers
4k views

Wrong filename encoding/decoding when downloading recursively with wget

I'm downloading files from a remote directory recursively using wget and whoever created the folders and files, used special characters such as è or Ó, when I download a single specificating the full ...
5
votes
1answer
1k views

difference between ifdown, ifconfig stop and ONBOOT=no

my ifcfg-eth1 config as below DEVICE=eth1 TYPE=Ethernet UUID=5e4f36f8-14eb-4f0c-8fa9-3af9be3899a7 ONBOOT=no NM_CONTROLLED=yes BOOTPROTO=dhcp DEFROUTE=yes IPV4_FAILURE_FATAL=yes IPV6INIT=no NAME="...
5
votes
1answer
5k views

What does “connections reset due to unexpected data” in netstat -s mean

I'm running a memcached server under heavy load from multiple web servers. While investigating some odd app level behaviour, we spotted that netstat -s on the memcached box was showing a lot of "...
5
votes
2answers
348 views

timing issue after route add/delete (route not used)

I have an application that is running a raw IP socket, destination of this socket is governed by routes installed via the 'ip route add' command. These routes can change during the lifetime of a ...
5
votes
0answers
4k views

NAT64 configuration with tayga on Debian 6

I'm trying to implement NAT64 with tayga on my server and came to a point where I'm not sure how to proceed. My server is connected via one IPv4 address and one /64 IPv6 address block to the internet....
5
votes
1answer
370 views

Samba4 locked pst files

i have a samba4 server that holds my clients outlook pst files, if the outlook client or the machine crashes i must go to the server to kill the PID manually. i saw there was "reset on zero vc =yes" ...
5
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2answers
1k views

How to add multiple CA certificates to LDAP client

I'm having trouble with adding a 2nd LDAP server into the client configuration. If I configure the client to use just either one, it works fine. So I'm sure both CA certificates work. I have tried ...
5
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0answers
5k views

how to tune NFS client on MacOS to get Linux like performance?

I have a NFS server running Linux and exporting a couple of shares. Both Linux and MacOS clients connect to the server, and while with the Linux clients I get ~ 75MB/s write speed, the MacOS clients ...
5
votes
1answer
4k views

How to mount vfat drive on Linux with ownership other than root?

I'm running into trouble mounting an iPod on a newly upgraded Debian Squeeze. I suspect either a protocol has changed or I've tickled a bug, which I don't know where to report. I'm trying to mount ...
4
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0answers
73 views

Linux VXLAN Hardware offloading

When looking at several guides to setup VxLAN networks on Linux there seems to be 2 options: Open vSwitch (OVS) Native Linux VxLAN device. When using OVS there is an option to use vxlan encap/decap ...
4
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0answers
377 views

Getting error “PHP Fatal error: Uncaught Zend\Uri\Exception\InvalidUriPartException” on AWS server

I am getting following error in error_log after moving the site (developed in Magento ver. 2.3.2) on new server (AWS Server): PHP Fatal error: Uncaught Zend\Uri\Exception\InvalidUriPartException: ...
4
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0answers
937 views

How to set Rx Queue = N in linux / in Qemu / KVM?

I have configured 8 multiple queues on my CentOS VM box (running on KVM). <interface type='direct' trustGuestRxFilters='yes'> <source dev='ens113f0' mode='passthrough'/> <model ...
4
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0answers
536 views

Format new parition of drive with xfs version 4 in Linux

I am working on an arcade machine and it cannot be updated unfortunately. A drive has corrupted data on it and in order to delete it I need to re-partition that drive. (I know it's the data and not ...
4
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0answers
198 views

why doesn't htop display the same process start time than ps

Ubuntu 16.0.4.5, htop 2.0.1 and 2.2.0 compiled from source. Showing the STARTTIME column in htop, displays Jan25 but ps -o lstart displays Sat Dec 15 20:58:46 2018 By looking at the pid it seems ...
4
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0answers
439 views

Compiling linux-tools tools for custom kernel

I have compile my own RT kernel for ubuntu 16.04 but when i try to use the perf or cpupower tool it says "cpupower not found for kernel 4.4.138-myrt". Then even if i have install the linux-tools-...
4
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0answers
2k views

Fastest way to sort very large files preferably with progress

I have a 200GB flat file (one word per line) and I want to sort the file, then remove the duplicates and create one clean final TXT file out of it. I tried sort with --parallel but it ran for 3 days ...
4
votes
1answer
383 views

nano very slow over ssh

Recently nano has started to be very slow when editing files over ssh. It's particularly slow when editing large files with syntax highlighting. It's most noticeable when yanking lines. There can ...
4
votes
1answer
883 views

ICMP Host Unreachable messages result in martian source packets

I've been trying to understand a peculiar behavior in our routing/firewall setup for quite some time now, but don't really understand what's going on. We have a firewall/router appliance that has two ...
4
votes
0answers
128 views

Network access stalls for some time on centos7 + zfs + samba installation

I have storage server with CentOS7 with 4 HDDs running on raidz (Raid 5). I access the files on it via samba. When I copy files from it or watch movies sometimes the reading from samba is blocked for ...
4
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0answers
161 views

Does an ESX hypervisor report stolen time correctly to linux guests

I have a bunch of debian 8 guests running on an esxi 6 hypervisor. top seems to always report 0 for its steal time counter. Is the stolen time reporting supposed to work when linux runs on esxi ...
4
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0answers
2k views

Postgresql fails to start with no such file or directory error?

I was juggling Postgresql versions and I think I shot myself in the foot during the renaming of something. I have 9.3 and 9.4 installed on an Ubuntu 14.04 station, and I wanted to go back to 9.3 so I ...
4
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0answers
2k views

Clarification regarding Deep Packet Inspection in the Linux Kernel's Netfilter section

The Linux Kernel provides Netfilter as a mechanism for both NAT and firewall functionality. Both of those functionalities require analysis and classification of incoming packets, which is dubbed "...
4
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0answers
1k views

Getting to enforcing google safe search using CNAME with unbound and nsd?

I am trying to implement this using Unbound and Nsd: https://support.google.com/websearch/answer/186669?hl=en To force SafeSearch for your network, you’ll need to update your DNS. configuration. ...

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