Questions tagged [linux]

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

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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 ...
sgt-hartman's user avatar
10 votes
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2k views

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 ...
dsmsk80's user avatar
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8 votes
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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: ...
Richard Downer's user avatar
8 votes
2 answers
1k 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 ...
sherpaurgen's user avatar
8 votes
0 answers
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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 ...
user394083's user avatar
8 votes
0 answers
6k 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 ...
memyself's user avatar
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7 votes
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Applying systemd control group resource limits automatically to specific user applications in a gnome-shell session

Having seen that GNOME now launches apps under systemd scopes I've been looking at a way to get systemd to apply some cgroup resource and memory limits to my browser. I want to apply a MemoryMax and ...
Craig Ringer's user avatar
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7 votes
2 answers
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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 ...
jgrump2012's user avatar
7 votes
0 answers
2k views

How can I let rsync display both total and partial progress?

I've found that rsync's total progress is (somewhat) shown with --info=progress2, while partial progress (i.e. the current file) is shown with --info=progress (or -P). Is there a way to show both? I'...
RedPixel's user avatar
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7 votes
0 answers
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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 ...
user avatar
7 votes
5 answers
6k 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/ ...
Steffan Donal's user avatar
7 votes
1 answer
860 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: [...
scarba05's user avatar
  • 333
6 votes
0 answers
994 views

AWS: Can't mount my restored volume (EBS snapshot)

I restored an EBS volume from AWS Backup and attached it to a new EC2 instance. When I lsblk I can see it under the name /dev/nvme1n1. More specifically the output of lsblk is: NAME MAJ:MIN RM ...
HelloWorld's user avatar
6 votes
0 answers
2k 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. ...
Quinn Comendant's user avatar
6 votes
0 answers
695 views

How to dump the kernel stack trace of a failed system call?

This is a canonical question. I want to understand why a specific system call is failing. Is it possible to display the kernel stack trace of the syscall: when the return is non-zero or is negative (...
Mircea Vutcovici's user avatar
6 votes
1 answer
1k 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 ...
Jordan Reiter's user avatar
6 votes
0 answers
164 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 ...
James Maroney's user avatar
6 votes
0 answers
7k 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 ...
DrDamnit's user avatar
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6 votes
1 answer
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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, ...
Nathan Basanese's user avatar
6 votes
1 answer
2k views

Inconsistent winbind info on Samba 4 AD domain controller

I've setup a Samba 4 AD domain controller on Debian Jessie (samba 4.2.10). Everything's working fine, except that winbind gives wrong user/group information. I have a sample user "testuser" and a ...
MasterM's user avatar
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6 votes
2 answers
998 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 ...
Kill Dash Nine's user avatar
6 votes
1 answer
210 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 ...
librett0's user avatar
6 votes
0 answers
6k 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 ...
Nagarz's user avatar
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6 votes
1 answer
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 ...
omnivir's user avatar
  • 99
6 votes
2 answers
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 ...
cclater's user avatar
  • 106
6 votes
1 answer
18k views

Tons of "invalid command \N" when restoring a dump

I'm following these instructions to upgrade postgres from 9.1 to 9.3: http://www.postgresql.org/docs/9.1/static/upgrading.html When I restore (Step 8), I get a ton of messages like this: psql:/mnt/...
Tony's user avatar
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6 votes
0 answers
21k 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 ...
quanta's user avatar
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6 votes
1 answer
4k 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 ...
Jim's user avatar
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6 votes
1 answer
5k 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 the ...
Norman Ramsey's user avatar
5 votes
1 answer
207 views

Unable to get my rsync of my software RAID 6 past 40MB/s. Looking for suggestions

Wondering what I could adjust to get my RAID 6 Software Raid to resync quicker. Currently it's proceeding at max of 64MB/s and averages to something around 25MB/s. Hoping to get it to 200MB: [...
DeliciousBoulder's user avatar
5 votes
0 answers
275 views

firewall-cmd to drop existing connections

I want to use firewall-cmd to temporarily block mysql port 3306, including existing connections. However after I remove MySQL service, only new connections are blocked. The existing connections are ...
GoYun.Info's user avatar
5 votes
2 answers
4k views

100% CPU usage reported, but no processes using the CPU

I am running Debian 10 (kernel 4.19.0-18-amd64) on bare metal and I have recently noticed strange CPU usage. Screenshot of htop, sorted by CPU% Screenshot of top, sorted by CPU% As you can see, 100% ...
tomf's user avatar
  • 51
5 votes
0 answers
13k views

Mount filesystem with "structure needs cleaning" on ext4

There is a created years ago(and many time resized from that times) filesystem with ext4. After power failure it stop to mount. When i try to mount it manually i receive an error: # mount /dev/space/...
undefine's user avatar
  • 1,076
5 votes
1 answer
5k views

RSYSLOG not creating tcp port

At a certain point this was working and I do not know what could have changed. No logs are going to the TFTP folder and instead I just see the error message posted below. I tried rebooting the server. ...
James's user avatar
  • 51
5 votes
0 answers
2k 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 ...
Chris Davies's user avatar
  • 1,720
5 votes
1 answer
5k views

systemd-journal Rate Limit

I have a service set up on CentOS 7 which outputs a lot of log messages, which results in this in the system log / journal: systemd-journal[xxxx]: Suppressed 864 messages from /system.slice/example....
David's user avatar
  • 51
5 votes
1 answer
2k 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 ...
Nils Toedtmann's user avatar
5 votes
0 answers
5k views

Troubleshooting `Buffer I/O error` on software-raid/md-device

I've got a RAID-5 mdadm array that reliably causes Buffer I/O error on dev md0, logical block 1598030208, async page read to be written do dmesg when reading that block. Of course, the read also ...
RQM's user avatar
  • 151
5 votes
0 answers
3k 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 "...
tomboy64's user avatar
5 votes
0 answers
2k views

Use of cores with `isolcpus` and `cpuset`

I have a Red Hat Enterprise Linux Server release 6.9 (Santiago) (I don't manage it). In the GRUB config file I have, let's say, isolcpus=2-32 (out of 36 cores). I also have a cgroup with cpuset=2-32 ...
Arkadiy's user avatar
  • 208
5 votes
1 answer
2k 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....
Daniel Hepper's user avatar
5 votes
0 answers
1k views

Auditd in a PCI-DSS-compliant Linux cluster

I'm familiar with some of the more common ways of configuring a Linux server to be compliant with PCI-DSS 3.2, at least to the requirements of SAQ A. A common concern is requirement 8.5 which ...
richard's user avatar
  • 151
5 votes
2 answers
6k views

Linux SMB to \\domainname ends up "tree connect failed: NT_STATUS_DUPLICATE_NAME "

Issue: From CentOS7 machine: smbclient -L %domainname%.com --user=%username% Result: tree connect failed: NT_STATUS_DUPLICATE_NAME This is especially when I try to connect to //domainname.com, ...
Mark's user avatar
  • 189
5 votes
3 answers
5k views

avoiding repetition in supervisord config for multiple programs

I have to run multiple instances of same app with slightly different settings. Only thing that changes is one command line parameter. So currently I've got script which looks something like this: [...
vartec's user avatar
  • 6,237
5 votes
0 answers
660 views

Send linux kernel paramters to VM guest in VMware

I have research a lot about this but I can't find anything that answers my question. My question is how would I send/pass linux kernel parameters to a VM guest in VMware vsphere (so I don't need to ...
krt's user avatar
  • 284
5 votes
1 answer
1k views

Can't communicate between multiple interfaces on same subnet

I have multiple ethernet interfaces on one machine, all on the same subnet. Normally these are set up to run on separate VM's, and I understand the limitations imposed by Linux as described here, but ...
Tanner's user avatar
  • 151
5 votes
1 answer
2k 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="...
Noob's user avatar
  • 363
5 votes
2 answers
588 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 ...
KillianDS's user avatar
  • 151
5 votes
0 answers
2k views

TCP connections in FIN-WAIT-2 state on linux not timing out according to tcp_fin_timeout

We run a service with lots of embedded devices in the field, their tcp stack is a bit buggy and sometimes does not close connections properly, resulting in some connections being stuck in FIN-WAIT-2 ...
yorick's user avatar
  • 151
5 votes
1 answer
2k views

keepalived config is not working correctly with virtualbox vms

my keepalived configuration is not working correctly. I have two virtual testing machines (virtualbox) to try some things out with keepalived/vrrp. Bot can ping each other flawlessly (internal ...
carrot's user avatar
  • 97

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