I can not publish new post in this blog. So many 500 error when I click publish, some times when I click signin.
The 500 internal error is because my blog, MovableType ate a lot of memory when it running. The Dreamhost is monitoring the resource user is using. It will kill the thread when it over the limit. Actually they don’t tell you the limit of it. They just tell you, it is time to upgrade to their VPS.
I connected the server through ssh. Run top command to see which one is more popular.
Yes, I found it. More than one mt-comments.cgi stay on the list.
To temporary solve the problem, I rename the mt-comments.cgi to other name. Then sign in the backend of MoableType.
Click Settings, Feedback, Uncheck the check box after Accept Comments.
Then, republish the whole site.
OpenSSH is very popular SSH server. Widely used on different Linux distribution. I used it for many years on my VPS server. It is easy to use, but security is the top issue for any server. Here is the top 6 security settings for Open SSH server.
To make it safe and minimize the risk, change the default setting and make it more safe.
OpenSSH setting file is located:
1) Only Use SSH Protocol 2
SSH protocol version 1 (SSH-1) has man-in-the-middle attacks problems and security vulnerabilities. SSH-1 is obsolete and should be avoided at all cost. Open sshd_config file and make sure the following line exists:
2) Allow Only Specific Users or Groups (AllowUsers AllowGroups)
By default anybody who is authenticated successfully are allowed to login. Instead you can restrict which users (or groups) you allow to login to the system.
This is helpful when you have created several user accounts on the system, but want only few of them to login.
This is also helpful when you are using NIS, openLDAP (or some other external system) for authentication. Every user in your company might have account on NIS, OpenLDAP etc. But, on a specific server you want only few of them to login. For example, on production system you want only sysadmins to login.
Add the following entry to the sshd_config file to allow only specific users to login to the system. In the example below only ramesh, john and jason can login to this system. Usernames should be separated by space.
AllowUsers ramesh john jason
Add the following entry to the sshd_config file to allow only the users who belong to a specific group to login. In the exampe below only users who belong to sysadmin and dba group can login to the system.
If you have two Dreamhost ftp account with SSH permission, and you want to transfer the content from account A to Account B, you need following script to do it.
It is simply one line shell command. I save it into a sh file. Schedule to run it every two hours.
Here is the script for you.
Name of Account A: ftp2010
Host name for ftp2010: hosting.mydomain.com
Name of Account B: ftp2011
Host name of ftp2011: hosting.yourdomain.com
The target is to transfer all files under ftp2010 to ftp2011 at hosting.yourdomain.com
To transfer the the large mySQL database, you need to learn how to use command to do it.
Large, means the database is bigger than 8 MB after compressing.
phpmyadmin, is a wonderful web tool for mySQL. But the limitation of upload is 8 MB. If the backup file is larger than it, you can not upload it, of course can not import it.
The platform I am working is Linux, Centos. It is ssh command environment.
1) Backup, export all tables of one database into one file.
I use this command to backup my forum database. The result is gzip file, means after compressing. I have a database is above 500MB. The gz file is about 125MB.
When I have the gz file, I can download it to my PC, or put it on other server for transferring.