Moved blog to EC2

I just finished moving my blog from Hostgator to my own EC2 t1.micro instance. While Hostgator shared hosting is cheap, running on shared servers is not so great. Had times when server was responding very slow.

I’ve decided to drop the “blog” prefix and keep it simple as http://getasysadmin.com. Hope there won’t be any problems with links.

In the process of moving to new server I changed the database from MyISAM to InnoDB, using the tips provided at step 4 from this post: 5 Essential Steps For Hosting A Scalable WordPress Blog Or Website. I also changed the theme of the blog. This one (wplook) is cleaner and better suited for my blog.

Apache2 worker vs prefork for ISPConfig benchmark

I’ve been running ISPConfig latest version(3.0.4) on Amazon cloud t1.micro instance for some time to host several small sites, mostly WordPress. I’m quite happy with the performance of the instance. The OS is Ubuntu 10.04 LTS. Until recently I’ve used the default mpm which is prefork, but I decided to test out worker also. If you are wondering I use mod_fcgid for all the sites. That being said I performed several tests with ab (apache benchmark) to see which mpm can server most requests per second.

While I do not claim this is the best setup, I think worker is better suited for me. Some people said they had problems because of mpm worker. So far so good, but will update this post if there are any issues.

Test results:

prefork

worker

Concurrency Level: 32
Time taken for tests: 7.834 seconds
Complete requests: 5000
Failed requests: 0
Write errors: 0
Keep-Alive requests: 4972
Total transferred: 84831033 bytes
HTML transferred: 83206915 bytes
Requests per second: 638.27 [#/sec] (mean)
Time per request: 50.136 [ms] (mean)
Time per request: 1.567 [ms] (mean, across all concurrent requests)
Transfer rate: 10575.21 [Kbytes/sec] received

Concurrency Level: 32
Time taken for tests: 7.096 seconds
Complete requests: 5000
Failed requests: 0
Write errors: 0
Keep-Alive requests: 4968
Total transferred: 84877824 bytes
HTML transferred: 83247322 bytes
Requests per second: 704.63 [#/sec] (mean)
Time per request: 45.414 [ms] (mean)
Time per request: 1.419 [ms] (mean, across all concurrent requests)
Transfer rate: 11681.17 [Kbytes/sec] received

Creating consistent backups for EBS with EXT4 and quota

What’s this about?
Data security and backups are very important aspects when you work with servers, especially if you are using cloud infrastructure. I am using AWS(Amazon Web Services) as my preferred IaaS, so the following how-to is tailored for Amazon EC2 instances using EBS as storage for the web sites files. On my instance I have Ubuntu 10.04 LTS installed and on top of it I run ISPConfig 3.0.4(latest version at the moment I write this article). Some of the programs required to run this setup were already installed, but it should be pretty obvious if you miss anything. If you need help you can either leave a comment or contact me via email.

The following setup will allow you to create an EBS using EXT4 as file system, with quota enabled on it(for ISPConfig) and weekly backups of the EBS. In case of instance failure you should be able to launch a new instance and attach the EBS, without losing any web sites files. In case of EBS failure you can recreate one from the most recent snapshot.

Create an EBS in the same zone as your instance and attach it to your instance as /dev/sdf. This can be easily done from AWS Management Console.

Install xfsprogs
sudo apt-get install xfsprogs

Create EXT4 filesystem on /dev/sdf
sudo mkfs.ext4 /dev/sdf

Now mount it temporarily
sudo mkdir /mnt/ebs sudo mount /dev/sdf /mnt/ebs

Stop the apache2 web server and copy the files to /mnt/ebs
sudo service apache2 stop cd /mnt/ebs sudo cp -rp /var/www/* .

Prepare quota
touch quota.user quota.group sudo chmod 600 quota.*

Add the entry to /etc/fstab
/dev/sdf /var/www ext4 noatime,nobootwait,usrjquota=quota.user,grpjquota=quota.group,jqfmt=vfsv0 0 0

Unmount the EBS and remount it to /var/www
sudo umount /dev/sdf sudo mount /dev/sdf /var/www -o noatime,usrjquota=quota.user,grpjquota=quota.group,jqfmt=vfsv0

Enable quota
sudo quotacheck -avugm sudo quotaon -avug

Start the apache2 web server and check that the web sites are working properly
sudo service apache2 start

Install ec2-consistent-snapshot script for weekly backups of EBS
sudo add-apt-repository ppa:alestic sudo apt-get update sudo apt-get install -y ec2-consistent-snapshot

Prepare first snapshot(I assume the cron will run as root user, hence I create the awssecret file in /root directory)
sudo touch /root/.awssecret sudo chmod 600 /root/.awssecret
Edit .awssecret and add following lines, in this order, replacing ACCESS_KEY_ID and SECRET_ACCESS_KEY with your own, both can be found under Account->Security Credentials:
ACCESS_KEY_ID SECRET_ACCESS_KEY

Test the snapshot creation with debug mode activated, replace VOLUME_ID with the right volume ID:
sudo ec2-consistent-snapshot --debug --description "snapshot $(date +\%Y-\%m-\%d-\%H:\%M:\%S)" --freeze-filesystem /var/www vol-VOLUME_ID

If everything went well you should be able to see your new snapshot in the AWS Management Console.

Finally add this to your root crontab (by running sudo crontab -e):
@weekly /usr/bin/ec2-consistent-snapshot --debug --description "snapshot $(date +'%Y-%m-%d %H:%M:%S')" --freeze-filesystem /var/www vol-VOLUME_ID>>/var/log/backup.log 2>&1
Make sure you put the correct VOLUME_ID!

This should be all, you now have all your web sites on EBS, quota is enabled and weekly backups enabled. I think I pretty much nailed everything you need in order to perform this setup, but if there are any issues feel free to leave a comment. Also I love getting feedback so if you found this article useful leave a comment also

Amazon RDS SUPER privileges

#1419 – You do not have the SUPER privilege and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable

This error occurs sometimes on RDS instances when you try to use procedures. You will soon find out that grant super privilege for a user won’t work. So the only way to make things work is to set log_bin_trust_function_creators to 1.

RDS console available at https://console.aws.amazon.com/rds/ allows you to create a new group and modify its parameters. Log in to RDS console, go to “DB Parameters Groups” and click the “Create DB Parameter Group”. Set the following
- DB Parameter Group Family: mysql5.1
- DB Parameter Group Name: mygroup
- Description: mygroup

Confirm by clicking “Yes, create” button.

Here comes the ugly part, since you cannot edit from the console the parameters (for the moment, I hope they are going to change that). You will need to log to your instance using SSH and download RDS cli from here: http://aws.amazon.com/developertools/2928?_encoding=UTF8&jiveRedirect=1

To do so right click on “Download” button and copy link location. In the SSH window use wget to download and unzip it:
wget “http://s3.amazonaws.com/rds-downloads/RDSCli.zip”
unzip RDSCli.zip

If you don’t have unzip you can quickly get it using “apt-get install unzip”(for ubuntu) or “yum install unzip”(for centos). Of course you will need root privileges.

After successfully unpacking the RDSCli cd to that directory and set a few variables. Following is an example on Ubuntu 10.04:
cd RDSCli-1.4.006
export AWS_RDS_HOME=”/home/ubuntu/RDSCli-1.4.006″
export JAVA_HOME=”/usr/lib/jvm/java-6-sun”
cd bin
./rds –help

If rds –help outputs no errors then you have set it correctly. Congrats. One more command:
./rds-modify-db-parameter-group mygroup –parameters=”name=log_bin_trust_function_creators, value=on, method=immediate” –I=”YOUR_AWS_ACCESS_KEY_ID” –S=”YOUR_AWS_SECRET_ACCESS_KEY”

The AWS keys can be obtain from your AWS account Security Credentials->Access Credentials->Access Keys.

Go to AWS RDS console, “DB Instances”, select your instance and right click “Modify”. Set “DB Parameter group” to “mygroup” and check “Apply Immediately”. Confirm with “Yes, modify”.

You are done

Mysql benchmark: RDS vs EC2 performance

the setup: 1 m1.small ec2 instance vs 1 db.m1.small rds instance, tests are being run from the m1.small instance. The goal is to determine how the site will perform when moving the database from localhost to a remote instance.

I used sysbench for mysql benchmarks. On a linux server running ubuntu 10.04 you can simply install it with the following command(it’s obvious but just in case):
sudo apt-get install sysbench

The first tests performed were m1.small EC2 instance running mysql-server 5.1.41-3ubuntu12.8 VS RDS instance type db.m1.small running mysql server 5.1.50. The test database had been set to 10 000 records, number of threads = 1, test oltp.
sysbench --test=oltp --mysql-host=smalltest.us-east-1.rds.amazonaws.com --mysql-user=root --mysql-password=password --max-time=180 --max-requests=0 prepare sysbench --test=oltp --mysql-host=smalltest.us-east-1.rds.amazonaws.com --mysql-user=root --mysql-password=password --max-time=180 --max-requests=0 run
The results

m1.small EC2 instance

db.m1.small RDS instance

OLTP test statistics:
queries performed:
read: 263354
write: 94055
other: 37622
total: 395031
transactions: 18811 (104.50 per sec.)
deadlocks: 0 (0.00 per sec.)
read/write requests: 357409 (1985.56 per sec.)
other operations: 37622 (209.01 per sec.)
Test execution summary:
total time: 180.0044s
total number of events: 18811
total time taken by event execution: 179.7827
per-request statistics:
min: 4.04ms
avg: 9.56ms
max: 616.04ms
approx. 95 percentile: 38.42ms

OLTP test statistics:
queries performed:
read: 188230
write: 67225
other: 26890
total: 282345
transactions: 13445 (74.67 per sec.)
deadlocks: 0 (0.00 per sec.)
read/write requests: 255455 (1418.74 per sec.)
other operations: 26890 (149.34 per sec.)
Test execution summary:
total time: 180.0573s
total number of events: 13445
total time taken by event execution: 179.9174
per-request statistics:
min: 9.08ms
avg: 13.38ms
max: 904.58ms
approx. 95 percentile: 20.99ms

As you can see the EC2 can perform 40% more transactions than the RDS instance. Nothing unexpected so far.

Time to move on and increase the number of threads to 10

m1.small EC2 instance

db.m1.small RDS instance

OLTP test statistics:
queries performed:
read: 264866
write: 94545
other: 37818
total: 397229
transactions: 18899 (104.97 per sec.)
deadlocks: 20 (0.11 per sec.)
read/write requests: 359411 (1996.22 per sec.)
other operations: 37818 (210.05 per sec.)

Test execution summary:
total time: 180.0462s
total number of events: 18899
total time taken by event execution: 1799.9289
per-request statistics:
min: 4.08ms
avg: 95.24ms
max: 2620.70ms
approx. 95 percentile: 445.91ms

OLTP test statistics:
queries performed:
read: 343812
write: 122772
other: 49109
total: 515693
transactions: 24551 (136.18 per sec.)
deadlocks: 7 (0.04 per sec.)
read/write requests: 466584 (2588.13 per sec.)
other operations: 49109 (272.41 per sec.)

Test execution summary:
total time: 180.2788s
total number of events: 24551
total time taken by event execution: 1801.8298
per-request statistics:
min: 13.41ms
avg: 73.39ms
max: 1126.02ms
approx. 95 percentile: 143.83ms

In this test the small RDS instance is faster than the EC2, 136 vs 105 transactions per second. I’ve also benchmarked a large RDS instance (the next one available after db.m1.small) and it got 185 transactions per second. Quite good, but the price is 4x higher.

The next test was performed vs a 10 million records, 16 threads. This time I only benchmarked a small and a large RDS instance. The large instance managed to do 228 transactions per second while the small one got a decent score of 127 transactions. One thing I noticed during this test is that the small instance started to use it’s swap, while the large one did not have this issue. This is probably due to the fact that 10M records db is aprox 2.5GB and the small RDS only has 1.7GB of RAM.

So if you are planing to grow and want an easy way to do it, switching your database to its own RDS is one of the first things you should consider. One of the immediate effects you will notice is that the CPU usage on the EC2 instance will be greatly reduced, leaving more power for the web server. You can easily increase the size and capacity of the RDS instance with just a few clicks. The backups are done automatically, which is great considering how many times I had to recover databases.

Mysql max_allowed_packet error

You are probably here because you tried to import a big database (several GB) and got the following error:
ERROR 1153 (08S01) at line 2533: Got a packet bigger than 'max_allowed_packet' bytes

If you have access to your mysql server and SUPER privileges things are easy, you just need to log in as superuser to mysql and type this:
mysql>set global max_allowed_packet=64*1024*1024;
and then import the database normally, just adding “–max_allowed_packet=64M” to the parameter list. Example:
$mysql --max_allowed_packet=64M database < database.sql
Everything is so easy. But if you are using Amazon RDS you are out of luck. You setup a user when you create the instance but of course it doesn’t have the SUPER privilege so if you try to execute the above command it will fail. Not even “grant super on *.* to myuberuser” will help you, no no. So after some googling and reading a lot of crap I found this blog which had the same error as mine. Yuppy! Thanks Henry!

The solution is to use DB Parameter Groups. Grab your mouse and start copy pasting fast.

Download Amazon RDS Command Line Toolkit
The latest version can be found here
wget http://s3.amazonaws.com/rds-downloads/RDSCli.zip unzip RDSCli.zip cd RDSCli-1.3.003 (this will surely change so make sure you cd to the right directory) export AWS_RDS_HOME=`pwd` export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk (this may vary depending on your java location and may not have to set it) cp credential-file-path.template credential-file vi credential-file (set your aws credentials there, use whatever text editor you like) export AWS_CREDENTIAL_FILE=${AWS_RDS_HOME}/credential-file cd bin ./rds --help

If everything went well you should get some output. On Henry blog he says he suggests that you create a parameter group. Well the reality is you have to create it since Amazon won’t let you modify parameters inside the default group.
./rds-create-db-parameter-group mygroup -f MySQL5.1 -d "My group" ./rds-modify-db-parameter-group mygroup --parameters "name=max_allowed_packet,value=67108864,method=immediate" ./rds-modify-db-instance YOURINSTANCENAMEHERE --db-parameter-group-name mygroup
Go to Amazon management console and check that the new parameter group is created and applied to your instance. You can begin now the import as you would do normally just add “–max_allowed_packet=64M” to the list of your options.

Hope it helps!

Amazon announces Free Usage Tier

Beginning from 1st of November you will be able to run a micro instance on Amazon cloud for free. Micro instance has 613 MB memory, up to 2 ECU(for short period bursts),32/64 bit platform and only has access to a 10 GB EBS(provided also for free). Also you get 5 GB to use with S3(simple storage) which is great for saving images (for example) and 30 GB data transfer(15 GB in and 15 GB out).

I believe this is a great opportunity to see what AWS is and also you may start to develop applications for cloud. You will probably want to use the EBS for MySQL storage and the S3 for media files.

Make sure you read all about this on their site before you use it and note that if you exceed the micro instance limits you are going to pay per use. Although the rates are low it never hurts to double check if you want to stay at 0$/month.

Once this offer is available (starting from 1st November) I am going to start testing a lot of stuff like how WordPress performs on this instance and how to install it so make sure you visit my blog from time to time! If you are interested in certain software installation on the amazon cloud platform feel free to send me an email and I will see if I can help.

Zend Framework provides cloud support

In a recent release announcement (for ZF 1.11.0 beta 1) I noticed that they now have Zend_Cloud which is, based on their description:

Zend Framework 1.11.0 markes the first official, stable release of Zend_Cloud, Zend Framework’s PHP version of the SimpleCloud API.

It offers support for some of the Amazon and Windows cloud solutions like S3/SQS and BLOB(spelled wrong Windows Azure’s blog storage)/Queue Service. While I didn’t work with Microsoft’s Azure, the S3 from Amazon is commonly used for all kinds of file storage. I believe it is great to be able to save files on S3, never having to fear about hard disk limitations and to some degree about their safety. While for small applications it might not be an obvious better solution, for applications that deal with a lot of files(like image storage for example) it is a big plus.

Although at the moment only S3 is interesting for me they stated they will be adding new features in the near future. Can’t wait that!