A pile of sysadmin notes!

Find your most sized files

noreply@blogger.com (randradas) — Mon, 02 Jun 2008 11:34:00 +0000

It is very easy with 'find' unix tool:


$ find / -size +100000k -exec ls -lh '{}' \;

Hard disk benchmark

noreply@blogger.com (randradas) — Wed, 23 Apr 2008 23:11:00 +0000

HD benchmarking is easy with bonnie++


# apt-get install bonnie
# mkdir /store/bench
# chown randradas:randradas /store/bench & chmod 755 /store/bench
# bonnie++ -d /store/bench -s 6600 -x 5 -u randradas:randradas -q -f 2>&1 | tee bonnie++.LOG &

Change 6600 to two times your ram to get a good result.

Forwarding proxy with Apache

noreply@blogger.com (randradas) — Tue, 15 Apr 2008 20:17:00 +0000

Edit prx.confwith the next Apache directives and adapt it to your port and directory requirements:


LoadModule proxy_module /usr/lib/apache2/modules/mod_proxy.so
LoadModule proxy_http_module /usr/lib/apache2/modules/mod_proxy_http.so
LoadModule authz_host_module /usr/lib/apache2/modules/mod_authz_host.so

Listen 8887

ProxyRequests On
#put < and > to the next directive
 Proxy *
   Order Deny,Allow
   Deny from all 
   Allow from 10.0.0.0/24
#put < and > to the next directive
 /Proxy

LogLevel warn
CustomLog /home/randradas/prx/access.log combined
ErrorLog /home/randradas/prx/error.log
PidFile /home/randradas/prx/apache.pid

Run the proxy with as normal user:


$ /usr/sbin/apache2 -f prx.conf

And then connect to the proxy from your http client, the server is listening in the 8887 port.

Resize Xen disk image

noreply@blogger.com (randradas) — Wed, 02 Apr 2008 10:49:00 +0000


losetup -f
losetup /dev/loop0 disk.img
e2fsck -f /dev/loop0
resize2fs /dev/loop0 6G
   resize2fs 1.40-WIP (14-Nov-2006)
   Resizing the filesystem on /dev/loop0 to 1572864 (4k) blocks.
   The filesystem on /dev/loop0 is now 1572864 blocks long.
e2fsck -f /dev/loop0
losetup -d /dev/loop0

losetup /dev/loop0 disk.img
fsck -n /dev/loop0
fsck 1.40-WIP (14-Nov-2006)
e2fsck 1.40-WIP (14-Nov-2006)
/dev/loop0: clean, 112769/786432 files, 458389/1572864 blocks
eddard:/xens/domains/beta.osor.eu# tune2fs -O ^has_journal /dev/loop0
tune2fs 1.40-WIP (14-Nov-2006)
eddard:/xens/domains/beta.osor.eu# e2fsck -f /dev/loop0
   e2fsck 1.40-WIP (14-Nov-2006)
   Pass 1: Checking inodes, blocks, and sizes
   Pass 2: Checking directory structure
   Pass 3: Checking directory connectivity
   Pass 4: Checking reference counts
   Pass 5: Checking group summary information
   /dev/loop0: 112769/786432 files (0.6% non-contiguous), 425587/1572864 blocks

For example, to create a 2GB sparse file-backed virtual block device (actually only consumes 1KB of disk):

    # dd if=/dev/zero of=vm1disk bs=1k seek=2048k count=1 

Make a file system in the disk file:

    # mkfs -t ext3 vm1disk 

(when the tool asks for confirmation, answer `y')

Populate the file system e.g. by copying from the current root:

# mount -o loop vm1disk /mnt
# cp -ax /{root,dev,var,etc,usr,bin,sbin,lib} /mnt
# mkdir /mnt/{proc,sys,home,tmp}

Tailor the file system by editing /etc/fstab, /etc/hostname, etc. Don't forget to edit the files in the mounted file system, instead of your domain 0 filesystem, e.g. you would edit /mnt/etc/fstab instead of /etc/fstab. For this example put /dev/sda1 to root in fstab.

Now unmount (this is important!):

    # umount /mnt 

In the configuration file set:

    disk = ['file:/full/path/to/vm1disk,sda1,w']

Export X11

noreply@blogger.com (randradas) — Fri, 07 Mar 2008 16:33:00 +0000

Scenario: Mac OS X (nieve)/server, Debian Etch (stark)/client
Objetive: Run a X application in my Mac OS

Run X11 in Mac OS

Open a terminal:


nieve:~$ xhost +stark_ip    (this step allows your client to connec to your server)
nieve:~$ ssh -X randradas@stark_ip
 ..
 ..
 Welcome to stark
 ..
stark:~$ export DISPLAY=nieve_ip:0.0
stark:~$ evolution &

Now you have Evolution running in your X11 server.

Apache2+SSL+SVN

noreply@blogger.com (randradas) — Thu, 21 Feb 2008 19:24:00 +0000


# apt-get install apache2 openssl ssl-cert
# mkdir /etc/apache2/ssl
# make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache2.pem
# chmod 600 /etc/apache2/ssl/apache.pem
# cd /etc/apache2/sites-available/
# cp default ssl
# a2ensite ssl
# a2enmod ssl
# vim /etc/apache2/ports.conf
   ..
   Listen 443
   ..
# vim /etc/apache2/sites-available/svn
   ..
   NameVirtualHost *:443
   VirtualHost *:443
      SSLEngine On
      SSLCertificateFile /etc/apache2/ssl/apache.pem
      ..
   VirtualHost

# /etc/init.d/apache2 restart

At this point you have an Apache server with SSL. Follow the next commands in order to integrate svn with Apache+SLL


# cd /
# mkdir /svnroot
# chown www-data /svnroot/
# su www-data -c "svnadmin create /svnroot/repository"
# su www-data -c "htpasswd -c -m /svnroot/.dav_svn.passwd testuser"
  ..
  ..
# vim /etc/apache2/sites-available/svn
  ..   
  Location /svn
       DAV svn
       SVNParentPath /svnroot/
       AuthType Basic
       AuthName "LibreForge Subversion Repository"
       AuthUserFile /svnroot/.dav_svn.passwd
       Require valid-user
  Location
  ..
# /etc/init.d/apache2 restart

Now you can use your repository with the testuser created recently:


$ svn co https://your.domain.tld/svn/repository
$ cd repository
$ touch testfile
$ svn add testfile
$ svn ci -m "restfile added"

Or see your repository through https, https://your.domain.tld/svn/repository

Google hack

noreply@blogger.com (randradas) — Sat, 05 Jan 2008 15:35:00 +0000

You can search indexed directories with Google using the next chain:

-inurl:(htm|html|php) intitle:"index of" +"last modified" \
+"parent directory" +description +size +(avi|mpg) "Kickboxer"

Substitute chains with VIM

noreply@blogger.com (randradas) — Sun, 02 Dec 2007 13:44:00 +0000

:%s/pattern/newchain/

This will substitute the first chain that matches the pattern, if you want to substitute all the chains that match the pattern the correct syntax is:

:%s/pattern/newchain/g

Excluding a directory with tar

noreply@blogger.com (randradas) — Mon, 29 Oct 2007 13:38:00 +0000


$ tar -cvf file.tar / --exclude "/path/to/directory"

You musn't to write / character and the end of the pattern you would like to exclude.

MySQL tricks

noreply@blogger.com (randradas) — Fri, 26 Oct 2007 13:09:00 +0000

New root password:


mysqladmin -u root password NEWPASSWORD

Change root password:


mysqladmin -u root -p oldpassword newpass

Create user account:


mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost'
    ->     IDENTIFIED BY 'some_pass' WITH GRANT OPTION;

MySQL query to CSV

noreply@blogger.com (randradas) — Thu, 25 Oct 2007 23:16:00 +0000

You again? uff.. well here is your reward.


select * from example into outfile '/tmp/example.csv' fields \
terminated by ',' lines terminated by '\n';

I'll see you ASAP looser.

CSV to MySQL

noreply@blogger.com (randradas) — Thu, 25 Oct 2007 23:02:00 +0000

Have you tried to import a CSV file to your MySQL database without success ? :), ok I'll make your day (Clint Eastwood).

prompt in your mysql console as create a table with the fields of your csv file, for example:


mysql> CREATE TABLE `test` (
    -> `fe` VARCHAR( 2 ),
    -> `fi` VARCHAR( 2 ),
    -> `fo` VARCHAR( 2 ),
    -> `fum` VARCHAR( 2 )
    -> );

Ok? the next step is to import the file into the recent created table:


mysql> load data LOCAL infile '/testfile' into table test \ 
fields terminated by ',' lines terminated by '\n';

/testfile is like this:


aa,bb,aa,rr
re,we,as,qw
ty,qw,as,as

Duplicate a directory structure, using rsync.

noreply@blogger.com (randradas) — Sat, 20 Oct 2007 03:06:00 +0000

You can duplicate a directory structure without duplicate the contents of these directories using 'rsync'.


$ rsync -avz --include='*/' --exclude='*' SOURCEDIR DESTDIR

Obviously login as root in the remote computer is a requirement whether you want to preserve the ownership.

Note: When I copy files to a remote computer I'm not capable of preserve the ownership of the files using this rsync options in spite of the rsync man says that.

CVS to SVN

noreply@blogger.com (randradas) — Sat, 20 Oct 2007 02:47:00 +0000

The next note is about migrate a cvs repository to subversion. Basically you need the 'cvs2svn' command in your system to do it.


# cd
# mkdir project
# cd project
# cvs2svn --dump-only --dumpfile ./project.dump \ 
/cvsroot/project/
# svnadmin create /svnroot/project
# svnadmin load /svnroot/project < ./project.dump
# chown -R www-data:www-data /svnroot/project/

That's all