Troubleshooting Unix / Linux Servers

Troubleshooting tips about Linux, *BSD, UNIX, Apple OS X, programming and MS-Windows servers and desktop systems ( rss feed ).

I‘m using RHEL 6 / CentOS 6.x and install the memcached server. However, whey I try to start the server using service memcached start command, I get the following error:

Starting memcached: failed to set rlimit for open files. Try running as root or requesting smaller maxconns value. [FAILED]

How do I fix this problem?

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I‘ve recently regenrated and uploaded a new public ssh-key using the ssh-copy-id command. Now I’m getting the following error:

ssh root@server3
Agent admitted failure to sign using the key.
root@server3′s password:

How do I fix this problem?

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I recently installed NFS server v4 on my HP Linux server. However, I’m not able to mount it from Linux nfs4 client using the following command:

mount.nfs4 server2:/data /data

I’m getting the following error:

mount.nfs4: mounting server2:/data failed, reason given by server:
No such file or directory

How do I fix this problem?

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I‘m using an external display with a MacBook Pro. I do not want to use the external monitor as a mirrored display. I need to move the dock and the menu bar to external monitor. How do I setup the external monitor as main display?

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I want to use my local machine as the X server over ssh. But when I try to run ssh -X -v user@server1.example.com to the remote machine, I get the following error:

debug1: Remote: No xauth program; cannot forward with spoofing

How do I fix this problem and use X over ssh?

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How do I find out if NFS server or service is running or not on my Linux or Unix based server?

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My CentOS Linux based server failed to boot with the following error:

read_urandom: /dev/urandom: open failed: No such file or directory

How do I fix this problem?

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