This is a test I wanted to make, using the css3 rotate() transformation.

I’m really happy with the initial result.

This script is using the following css declarations:

-moz-transform: rotate(Xdeg);

-webkit-transform: rotate(Xdeg);

transform: rotate(Xdeg);

(replace X with the proper degrees you want to rotate)

I’ve tested this on FF 3.5, Safari 4, and Chrome 6 and they all seem to be handling it pretty good.

I’d love to hear comments and suggestions about this.

demo

This collection contains custom map marker icons tagged with all English letters (A-Z) and number 0-99.

Have fun using it and let me know if anything interesting comes up.

Download (13.5 MB, zip)

lwtMapIcons by Vassilis Dourdounis is licensed under a Creative Commons Attribution 3.0 Greece License.

telnet localhost 11211

The list of commands is as follows:

Get stored data

get <key>*

Returns the value stored for this key. You can specify more than one keys separated by spaces.

Store data

[set|add|replace|append|prepend] <key> <flags>
<exp_time> <bytes> [no_reply]

The arguments are:

• flags: an arbitrary 16-bit unsigned integer (written out in decimal) that the server stores along with the data and sends back when the item is retrieved.
• exp_time: expiration time in seconds. If it’s 0, the item never expires (although it may be deleted from the cache to make place for other items).
• bytes: the number of bytes in the data block to follow, *not* including the delimiting \r\n. <bytes> may be zero (in which case it’s followed by an empty data block).

After the command hit Enter and input the data block of size <bytes>.

Return values:

• STORED
• NOT_STORED

Delete data

delete <key> [<time>] [noreply]

Delete a key.

• time: the amount of time in seconds (or Unix time until which) the client wishes the server to refuse “add” and “replace” commands with this key.

Flush all stored data

flush_all

Flashes the entire cache.

Other commands

stats

General statistics

stats slabs

Memory statistics

stats memory

Memory statistics

stats items

Higher level statistics

quit

Quit the telnet interface

Just reducing the DNS TTL’s won’t always work as expected, as many providers have been reported to ignore the TTL values.

So, instead of just changing the TTL to a small value and pray, there is a small hack you can apply to this particular situation.

Disclaimers:

• This solution only applies to web traffic. For other types of data (such as email) it offers nothing.
• This assumes that you are using Apache as your webserver, although the same principle should apply to other webservers as well.
• I assume you know the basics of a domain transfer. This guide does not go into much detail about managing DNS records.

Phase one (a couple of days before the move)

Change your DNS TTL values to a smaller value. Typically this would be set to 86400 seconds (24 hours) or maybe 14400 (4 hours).

Specifying a minimum TTL depends on your server’s traffic. Set it too low and you’ll get flooded with DNS queries. Set it to high and you’ll need to wait longer for the DNS change to happen (this will not be much of a problem with the method proposed here, it will just be… longer )

Let’s say you set it to 1800 seconds (30 minutes). This will take 36 to 72 hours to propagate across the internet, though as previously mentioned, some clients may choose to ignore this, therefore you can’t count on that.

Create the vhost for the domain that should be moved on the target server.

Make sure mod_rewrite is enabled on the old server (you are going to need this later).

Phase two (t minus some hours)

Make sure your code is in place and running on the target server (do a test migration of the database and content).

Create a new subdomain (vhost) on the target server called something like migration_temp.<your-domain-name.com> (don’t worry, this wont be visible to your visitors – you can name it whatever you want). This subdomain should be serving the same content as the domain you are moving, so make sure it points at the same path as your domain. Careful: use a non-existant subdomain, so that you wont have to worry about it’s DNS propagation.

Add a new A record for this subdomain to your DNS server with the IP of the target server.

Phase three (changing the servers)

Crack your knuckles for this one.

The actual down time depends on how quickly you can move your database and content files from one server to the other.

When ready to move, make sure that no further changes can be made to the old server (through a maintenance page or something like that).

Then move the databases and content files to the new server.

Here come’s the clever part.

On the old server, add an .htaccess file on your site’s base directory with the following lines:

Options +FollowSymlinks
<IfModule mod_rewrite.c>
 RewriteEngine on
 RewriteRule (.*) http://migration_temp.your-domain-name.com/$1 [P]
</IfModule>

What this does is act as a proxy, redirecting all requests to the new domain. This is transparent to your visitors – they still see the standard domain in the URL.

Hard part is over. Re-enable your site and all requests should now be served by the new server. We still need the old server to temporarily proxy the requests to the new one.

Sit back and relax a bit as the load lingers on the old server, while starting to thrive on the new one.

Then, go ahead and change the DNS records to direct to the new server. (Don’t forget to restore the TTL to something more practical).

After a few days, you can confidently disable the old server.

My webserver is a CentOS 5 webserver with cPanel.

Setup memcached

1. Setup libevent

This is a library needed by memcached. Install it:

wget http://monkey.org/~provos/libevent-1.4.14b-stable.tar.gz
tar zxvf libevent-1.4.14b-stable.tar.gz
cd libevent-1.4.14b-stable
./configure
make
make install
cd ..

2. Setup memcached

Get and install the latest memcached code:

wget http://memcached.org/latest
tar -zxvf memcached-1.x.x.tar.gz
cd memcached-1.x.x
./configure --with-lib-event=/usr/local/
make
make install

3. Add the libevent library to the path

If you attempt to run memcache at this point you will probably get an error for missing the libevent library. Register it:

touch /etc/ld.so.conf.d/libevent-i386.conf
echo "/usr/local/lib/" > /etc/ld.so.conf.d/libevent-i386.conf
ldconfig

4. Test memcached

memcached -d -m 1024 -u root -l 127.0.0.1 -p 11211

This opens up memcached server with 1024MB of RAM on port 11211.  (memcached -h for more on options)

Connect via telnet to make sure it’s up:

telnet localhost 11211

Ctrl-C to exit. Done.

Setup the PECL extension for PHP

1. Setup PECL memcached

pecl install memcached

Careful: Notice the “d” at the end. Pecl also hosts an extension called “memcache”. This is a different implementation. All the examples listed below use “memcached”.

Add this line to your php.ini:

extension = “memcache.so”

2. Test the installation

Create a new PHP file within your document root directory with the following contents:

<?php
$memcache = new Memcache;

// Connect
if(!$memcache->connect('localhost', 11211)) {
 die('Could not connect to server');
}

// Set the cache
$memcache->set("test_hash", "It works, mate!", false, 400);

// Get the cache
if ($ret = $memcache->get("test_hash")) {
 echo $ret;
}
else {
 die('Could not retrieve data from memcached');
}
?>

Save it and point your browser to this file.

You should get: “It works, mate!”

For more information on how to use memcached, check out the memcached manual pages.

Further steps

Starting memcached as a service

Check out this tutorial by Danny Bembibre.

Monitoring memcached

This has given me some hard time.

There are all sorts of tools to monitor the cache, some are web-based, some are local applications. I’ve had tough luck finding something that I could recommend.

The only one I’m currently using is a top-like command line tool named: memcache-top.

To install and run it:

wget http://memcache-top.googlecode.com/files/memcache-top-v0.6
chmod +x memcache-top-v0.6
./memcache-top-v0.6

That’s all. I hope this will be useful to all you out there.

If you have any comments please do not hesitate to contact me.

Ok, this bares a striking resemblance to a really inspiring presentation in TED a few years… Aaaah, Google has acquired the technology featured in that presentation. Figures…

Using this tool gives you the ability to explore public data, in a unique and revolutionary way (I strongly advise you to have a look at that presentation if you haven’t), and provides elaborate insights on how diverse factors can affect each other.

Google public data explorer

It would be very interesting if Google where to release some kind of API or code for this functionality.

I’ve ported my javascript slideshow to jQuery and this is what came about:

jQuery Blinds

Enjoy!

They are actually Japanese letters.

It’s a katakana syllabogram, pronounced “tsu”

There’s also this:

This one’s called “she”

Besides their obvious contribution to the Japanese language, they are pretty awesome alternative smilies.

So this turned out:

It’s a simple icon set to be used with interactive maps.

The file contains 3 color variations of all capital latin letters and numbers from 0 to 99 in PNG format.

Enjoy and let me know if something nice comes out of this!

lwt_map_icons.zip (856 KB)

lwtMapIcons by Vassilis Dourdounis is licensed under a Creative Commons Attribution 3.0 Greece License.

Blog Setup: 40 Practical Tips

It’s a very useful resource and I’m still checking out some of it’s recommendations.