DreamHost PS
From DreamHost
DreamHost PS or DreamHost Private Server is DreamHost's premium shared hosting service. Available as an add-on to an existing DreamHost plan, DreamHost PS uses Linux-VServer to create a "virtual machine" that protects a user's CPU and RAM resources from other users on the same physical machine.
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Features
- Protected CPU and RAM
- Ability to burst up to the full 2.3 GHz CPU and double the RAM
- Persistent processes are allowed (and will never be killed)
- Ability to alter the memory and CPU allocation on the fly, without the need to reboot
- Ability to reboot the server from the Control Panel
- Historical memory and load graphs can be viewed on the Control Panel
Important Note: If you order a PS you now have the option to move your entire shared hosting account is moved over to it OR you can leave it empty and just create new users on the PS service and move specific domains over as you like. See the section below for details and instructions.
Persistent Processes
Unlike the regular shared hosting setups, the Dreamhost PS allows for persistent processes to run. Regardless of how long it takes to run these processes (web invoked, console invoked, cron, or otherwise), the processes will never be killed by the server. It should be noted, however, that they are subjected to both CPU and RAM throttling.
In regards to the latter (CPU and RAM throttling), it seems from practice that when a process begins running, it will consume the level of RAM or CPU that it feels necessary. Although your PS may be confined to 150mb RAM / 150 MHz CPU (as an example), it is possible to exceed this number, though only briefly. As soon as the system is 'aware' that you have exceeded your maximum allowable commitment, the process will be throttled accordingly. In many cases, even though the process will continue to run, it may run VERY slowly. You may therefore discover that custom scripts will still run, but instead of taking seconds to complete, they may take several minutes.
Dynamic Server Settings Adjustment
Many of the key configuration options for your DreamHost PS server are configured on the fly by our automation system to best take advantage of your available server resources. For instance, if you have a 150MB PS server Apache will be configured to use a relatively small amount of memory, and if you have more memory it will be configured to use more memory. Currently this is handled automatically for key Apache settings and it will be extended to other configuration options over time.
Wildcard DNS
See this article for more information.
Moving Specific Domains From Shared to PS Server
If you have selected the option to have the PS web server added to your account but want to move domains over to it yourself one at a time (rather than all at once) follow this procedure (to move a domain over to the PS server).
- If you have not already done so create your first FTP/shell account on the new PS server.
- Go to (USERS > MANAGE USERS) and click on the "Add a new user" button.
- Select the options as necessary and make sure to select your PS server from the "Server:" drop-down menu.
- Click on the "Add user" button to push this new user account into place (which could take about 15 minutes).
- Go to (DOMAINS > MANAGE DOMAINS) and click on the "Edit" button for the hosting option you'd like to move to your PS server.
- Select the (PS) user from the "FTP user / CGI-runs-as user:" drop-down menu that you want this domain to use.
- Do not check the box labeled "Copy domain's files to new user?", as this feature has not yet been implemented for server-to-server changes.
- Click on the "Change fully hosted settings now" button to push the new configuration in place (which will take some time).
- Using RSYNC, you'll need to copy all the files for your domain over to the new user on the PS, under that domain's Web Directory. Move a domain to PS
NOTE: As with all changes that require DNS updates (like this will) it could take between 4-72 hours for the DNS updates to fully propagate throughout the entire Internet. However, we'll keep the old hosting option enabled (on the old server) for 5 days so service will not go down during the transition.
Apache Configuration / Management
httpd.conf
Only edit this file if you're sure you know what you're doing. Always Backup first.
Location
/usr/local/dh/<psServerName>/etc/httpd.conf
Rebooting Apache
Warning: This act will disconnect any active connections (i.e. users, downloads, etc) and may result in angry users
Create a PS Root user through the DreamHost Panel
Log in using that user.
Restart Apache
sudo /etc/init.d/httpd2 restart apache2-<PsServerName>
So it might look like
sudo /etc/init.d/httpd2 restart apache2-ps1111
