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1500 questions
44
votes
7 answers

Why can't you fsck a mounted partition?

It's well-known that you should never fsck a mounted partition. I can understand how this could easily lead to corruption if the filesystem is written to by fsck (e.g., the -a option is used), but why can't read-only checks be run on mounted disks?
mike
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44
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7 answers

Troubleshooting latency spikes on ESXi NFS datastores

I'm experiencing fsync latencies of around five seconds on NFS datastores in ESXi, triggered by certain VMs. I suspect this might be caused by VMs using NCQ/TCQ, as this does not happen with virtual IDE drives. This can be reproduced using…
exo_cw
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44
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1 answer

How do I tell what is running on which ports in Ubuntu?

How could I tell what is listening on which ports on Ubuntu? In other words, how do I get a list of ports that are in use?
Genadinik
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44
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3 answers

How do I clear the "s" permission on a directory in Linux?

I have a directory that is showing up with the permission mask drwsrwsr-x. When I try to reset the permissions to 755 the S still remains. What is the "s" and why cant I change the permissions back to 775 (drwxrwxr-x)?
Matt Elhotiby
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44
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6 answers

How do I access a local web server on my laptop from another computer?

I have an app running on my computer at 127.0.0.1:3000 I would like to access that app from an iPhone connected to the same network. I have done this before but blanking out on how I did it. Any ideas?
Tony
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44
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3 answers

What's best practice for communication between Amazon EC2 instances?

I've been setting up Amazon EC2 instances for an upcoming project. They are all micro instances, running Ubuntu Server 64bit. Here's what I've setup so far: Web Server -- Apache Database Server -- MySQL Development Server -- Apache & MySQL File…
ks78
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44
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5 answers

Specify SSH Port for Git

I use a non-standard ssh port (1234) for most of the servers I connect to. So in my ssh config file I have: Port 1234 But github.com uses port 22. When I try to connect to github it obviously tries to use port 1234. Right now I have to edit my…
James Ward
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44
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2 answers

Using dot (.) as delimiter to specify group in chown

I've always done: chown nimmylebby:admins file I see that this also works: chown nimmylebby.admins file Might seem like a silly question but I'm genuinely curious on how the latter works. It isn't documented in my chown's manpage (GNU coreutils…
Belmin Fernandez
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44
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4 answers

What's the best way to get info about currently unmounted drives?

First, the situation: I've got a Linux computer with two eSATA drive bays that accept removable SSD drives. I'm trying to write a little GUI application that makes it easier for the user to mount/unmount/format/backup/etc the drives that he puts…
Jeremy Friesner
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44
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10 answers

keyboard shortcut to quit 'telnet'

on Windows XP/server 2003 When telnet some remote host on a specified port, after connection established, sometimes press ctrl+] doesn't quit. Is there any command can quit instead of just close the command line window? Thanks. EDIT: But sometimes…
Stan
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44
votes
7 answers

Is Arch Linux suitable for server environment?

Do you consider Arch Linux suitable for server environment? Its rolling release model and simplicity seems to be a good thing, because once you installed it, you do not need to reinstall like the release model from other distros. But that constant…
FooBar
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44
votes
11 answers

How to monitor and log the memory/cpu usage of processes over time?

I am looking for a way to diagnose issues, such as swap death, where a balooning memory process fills up swap and kills the whole machine (such as apache). I'm already using cacti and I can set up nagios (though would rather not) or munin but as far…
Artem Russakovskii
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44
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2 answers

Merging variable with string in config file

I the have following setup in my conf file upload_set_form_field $upload_field_name.name "$upload_file_name"; But I want change chosen param name to: upload_set_form_field ($upload_field_name+"[name]") "$upload_file_name"; So I can get…
Swistak
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44
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5 answers

How many Context Switches is "normal" (as a function of CPU cores (or other))?

Hi Linux/UNIX Overlords, Do any of you have a rule of thumb as to how many context switches (per processor core) is Normal on a Linux server? My college here brought it up, and he's seeing 16K on a 8-core x86_64 machine. Here are some stats from…
khosrow
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44
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5 answers

Best system for managing ssh keys?

I've got several client computers (i.e. laptops, desktops, etc.), and I connect to several server machines that I manage, and I log into them all via SSH. I can imagine several schemes of managing ssh keys that would make sense, and I'm curious…
slacy
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