The cPanel Admin » tips

Removing WHM Disk Space Errors

Vanessa — Wed, 13 Apr 2011 17:45:01 +0000

If your server is approaching 99% disk space, your users may be aware of this before you are. At the 1% free margin, the following error will pop up when accessing certain features in cPanel and WHM:

Sorry for the inconvience!
The filesystem mounted at / on this server is running out of disk space. cPanel operation has been temporarily suspended to prevent something bad from happening. Please ask your system admin to remove any files not in use on that partition

While 99% may seem like a dangerous limit, servers nowadays are getting rather large. If you have a server with over 3T of disk space, that 1% free could be well over 100G of space – space that would seemingly become waste.

Until this limit is removed in a future release, you can actually trick cPanel into thinking that the server has more space available. The key is the cache files located in /root/.cpanel/datastore, specifically the file _bin_df_-P_-k_-l.

If you edit that file and change the occurrence of 99% to a lower value, you’ll see the restricted cPanel and WHM features return to normal. Keep in mind that the cache regenerates, so in some cases it may be appropriate to create a cron job to periodically change the file.

Of course, if 99% disk usage on your server leaves you with a minuscule amount of space, you’ll want to remove some files or add additional storage. The following articles may be useful:

Thanks to my colleague Lee for sharing this tidbit of info

10 Tips for Improving Email Delivery

Vanessa — Mon, 25 Oct 2010 17:32:48 +0000

One of the most common problems that hosting providers face is the issue of user email not being delivered to other mail servers. Not only does it annoy the end user, but it’s extremely frustrating for the server administrator to deal with since there’s not always a clear indication of why email doesn’t get delivered successfully. In this post I’ll explain a few tips for helping improve the reliability of your mail server, and some tips you can give to your end users that send mailing lists.’

Note: You can’t control the incoming email policies of remote mail servers or RBL’s. However, most email providers will not intentionally inconvenience their own users by blocking legitimate email, so if you continue to have problems, I’d recommend contacting the email administrator of the remote server.

1. Do you look like a spammer?

First of all, if you’re sending out massive mailing lists, whether you consider it spam or not, you’re asking for it. Out of a list of 100,000 people, you can expect that a couple hundred of them are going to prompt spam complaints to your email provider, especially of the emails are of a “spammy” nature. If you’re not sure where you sit on the line between spam and email marketing, take a look at this post.

2. Practice proper mailing list etiquette

As a mailing list grows, you’re occasionally going to have email addresses that become invalid, or users that no longer want to receive your email. Don’t think that by hiding your opt-out link, you’re going to keep a subscriber. The recipient is more likely to mark your email as spam than hunt around for a way to remove their email address from your list, so make things easier by putting your opt-out link at the top with a reminder of why you are sending the email. For example:

You are receiving this newsletter because you purchased a product on mywebsite.com and requested to receive notifications. If you no longer want to be part of this mailing list, please click

That being said, it’s extremely important that you promptly honor opt-out requests, and regularly check for bounced email for addresses that may no longer exist.

In addition to this, when sending email locally, your SMTP hostname should simply be “localhost”.

3. Limit outgoing email

If you’re a hosting provider and aren’t specifically catering to users that do bulk mailing, you may want to limit how much email each users can send, and advise users with large mailing lists to use services like Constant Contact. Tweaking a mail server to effectively send huge amounts of email without issue can be very difficult, and isn’t something I’d recommend even offering for shared hosting platforms. In a shared environment where the actions of one user can affect many, outgoing email should be limited and then allowed on a per-case basis. There are two simple ways to do this:

In WHM > Tweak Settings, set the outgoing mail limit . You can specifically allow domains to send more by adding them to /var/cpanel/maxemails on versions 11.26 and lower, or adding a MAX_EMAIL_PER_HOUR option to /var/cpanel/users/$user for cpanel 11.28 and higher.
In exim.conf, set the following options:

recipients_max_reject = true

recipients_max = 50

The best way to do this so the change is retained over cPanel and Exim updates is to add the options in /etc/exim.conf.local under @CONFIG@, then run /scripts/buildeximconf

Exim considers each email as one email, regardless of how many recipients are in it. This may be an inconvenience to some users, but in reality any mailing list should be sent as one recipient per email. For larger organizations that use mailing lists for discussion, a listserv software like Mailman is a better solution.

4. Tighten up your mail server

If you’ve ever wanted to be the target of a spam hack, allowing PHP nobody mail is the best way to accomplish this. Hopefully by now you’re running suPHP, but if you’re still running PHP as a DSO, whenever a PHP script uses the mail() function to send email it’s going to do so as the user “nobody”, or whatever user that Apache runs as. Since the user “nobody” is a system user, it bypasses mailing limitations that you may have already set up via cPanel or exim.conf. This means that a rogue mailing script on your server can send out unlimited amounts of email and cause your server to get blacklisted. You can adjust this setting in WHM > Tweak Settings.

You’ll also want to make sure that SMTP Tweak is turned on:

/scripts/smtpmailgidonly on

It’s also a good idea to require sender verification, which can be enabled in WHM > Exim Configuration Editor

5. Always use SMTP

Similarly, mailing list software should be configured to use SMTP with a valid email address, username, and password. Don’t rely on sendmail or the php/perl mail functions – you need to send as a valid authenticated user. Most mailing list software supports the use of SMTP, and using PHP or perl it’s very easy to incorporate SMTP authentication.

6. Use DomainKeys and SPF records

You want other mail servers to know that when they get mail from you, it’s actually from your server and not spoofed. Consider using DKIM and SPF records to allow remote mail servers to authenticate your email. You’ll find that this may instantly improve your email delivery to services like Yahoo, MSN, and Hotmail.

See: Installing DomainKeys and SPF Records

7. Subscribe to Feedback loops

It’s very important for email administrators and hosting provides to subscribe to feedback loops. Many remote mail and blacklist providers offer them, and they can be a very useful tool for identifying possible spammers on your network, as well as preemptively resolving issues with mailing lists. If you don’t have an Abuse contact set up your domain and IP addresses, you should do that now – and register your IP(s). AOL, Hotmail, Yahoo, and Spamcop are excellent ones to be on. It’s also important to have your abuse@domain.com address set up so people can contact you if they want to report spam from your server or network.

8. Monitor your IPs

As easy as it is to get blacklisted on the various RBL’s out there, you’ll want to be checking if your IPs may be listed and therefore causing your email to bounce. RBLmon.com is a good way to get started, or you can implement blacklist checking into your existing monitoring solution. The goal is to know when your IPs are blacklisted as soon as possible.

9. Use different IPs for email

By default, when you send email your email will go out on the main IP of the server. For sites that send large amounts of email, consider putting them on separate IPs so that they don’t affect the mail delivery of other users on the server, or the network in general.

See: Changing Exim’s Sending IP

10. Set up your DNS properly

It should go without saying that whatever IP you use to send mail should have a proper reverse DNS record, and the forward DNS of that PTR should match. For example, if your mail server is named mail.mydomain.com and points to 5.6.7.8, then the PTR for 5.6.7.8 should also be mail.mydomain.com. Ideally these records should match the EHLO/HELO name given by your MTA (Exim). This name can be altered in /etc/mailhelo if you have this option checked in WHM > Exim Configuration Editor.

Skipping the WHM Setup Wizard on New Servers

Vanessa — Fri, 23 Jul 2010 14:26:43 +0000

If you have a fully automated cPanel/WHM setup method used to deploy a large number of servers, you’ve probably found it to be annoying that upon loading WHM for the first time, you’re greeted with a setup wizard that you have to click through. To skip this wizard, all you need to do is touch a file:

touch /etc/.whostmgrft

This will tell WHM to skip the setup wizard altogether. However, if you haven’t already, you’ll want to add the following pieces to your automation which are usually configured in the setup wizard:

IMAP – /scripts/setupmailserver (courier | dovecot | disabled)
DNS – /scripts/setupnameserver (bind | nsd | disabled)
FTP – /scripts/setupftpserver (pure-ftpd | proftpd | disabled)

You should also create the /etc/wwwacct.conf file, with the following contents:

ADDR 123.456.789.123 CONTACTEMAIL your@emailaddress CONTACTPAGER DEFMOD x3 ETHDEV eth0 FTPTYPE pureftp HOMEDIR /home HOMEMATCH home HOST server.domain.com LOGSTYLE combined MINUID NS ns1.yourdomain.com NS2 ns2.yourdomain.com NS3 NS4 NSTTL 86400 SCRIPTALIAS y TTL 14400

Derived from : http://www.cpanel.net/blog/integration/2010/05/skipping-the-whm-getting-started-wizard.html

Allowing Users to Customize AwStats

Vanessa — Wed, 21 Jul 2010 15:39:48 +0000

You can allow users to use their own configuration file for AwStats in case they are in need of customizations not provided by the server’s main config. To enable this option, add the following to /etc/stats.conf:

allow_awstats_include=1

Alternatively, you can go to WHM > Statistics Software Configuration, and click on Allow Awstats configuration Include file

This will allow users to have an awstats.conf.include file in /home/$username/tmp/awstats, which can be used to override settings from the main AwStats configuration for the server.

Manually Rearranging Accounts

Vanessa — Wed, 14 Jul 2010 19:42:07 +0000

There was a situation today where I had to mass-move a bunch of accounts from one partition to another. WHM’s Rearrange an Account function does this one account at a time, but to move over 50 of them, a more scripted solution was necessary. Here’s how I did it on a live server without causing any downtime:

Scenario: Moving over 50 cPanel accounts from /home4 to /home3 on a live dedicated server

Step 1: Grab the list of users

Done with a simple one-liner:

for user in `cat /etc/passwd | grep /home/ | cut -d: -f1` ; do echo $user >> /root/users ; done

Step 1: Rsync all the data over

This part can be fairly CPU-intensive, so you may want to bandwidth-limit or renice the rsync which will slow the transfer, even if done locally. You need to copy the data on one disk to the other:

for user in `cat users` ; do rsync -av --bwlimit=8000 --delete /home4/$user /home3 ; done

You may want to run this command a few times depending on how much data is being moved over.

Step 3: Update configuration

Paste the following commands into a file (replacing the partition names with the ones pertaining to your server), chmod 755, and run:

for user in `cat users` ; do

replace /home4/ /home3/ — /var/cpanel/userdata/$user/*
replace /home4/ /home3/ — /etc/proftpd/$user
replace /home4/$user /home3/$user — /etc/passwd
ln -s /home3/$user /home4/$user
replace /home4/$user /home3/$user — /home3/$user/etc/*/passwd

done

Now, run:

/scripts/rebuildhttpconf && service httpd restart

service pure-ftpd restart (or proftp)

When you’re sure that everything is moved over, you can remove all the user data from the old partition.

Performance Tip: Disable Optimizefs

Vanessa — Tue, 22 Jun 2010 13:21:29 +0000

CPanel utilizes a script called “optimizefs” that removes the atime attribute from certain files on the system. For larger servers, this can create a lot of i/o load for a problem that can be fixed simply by mounting your file systems with the noatime flag if your file system is ext2 or higher.

The atime attribute is used by Linux to mark when a file was last accessed, and is understood to be a resource drain when enabled for an entire filesystem. cPanel attempts to address this by removing atime attributes from a specific list of files. You may see a command like this in your root crontab:

45 */8 * * * /usr/bin/test -x /usr/local/cpanel/bin/optimizefs && /usr/local/cpanel/bin/optimizefs

This cron basically applies the following command to a number of files and directories:

chattr +A /path/to/file/or/directory

Instead of using cPanel’s band-aid fix, it’s preferred to remove the atime attribute from the filesystem altogether. To do this, add noatime to the file system properties for each usable partition listed in /etc/fstab. For example:

LABEL=/ / ext3 defaults,usrquota,noatime 0 0 /tmp /var/tmp ext3 defaults,usrquota,bind,noauto,noatime 0 0

Then remount each file system. For the example above using the root partition ( / ):

mount -o remount /

*In some cases, a reboot may be necessary

Now, you can remove the cron job and still get the same benefits of not having your operating system record file access times:

sed ‘/optimizefs/d’ -i /var/spool/cron/root && service crond reload

Additional Resources:

http://www.faqs.org/docs/securing/chap6sec73.html

Tips to Reduce Your Customer Support Costs

Mark — Tue, 22 Jun 2010 01:05:06 +0000

When hosting websites, whether as a mainstream hosting provider, a hobby, or to supplement another service, it’s your job to make sure your customers have access to technical support in case they need help. Customer support is one of the highest expenses that a web host can encounter. Just my making a few small changes, you can reduce the amount of customers that contact you for help, and increase your profit margin.

Revamp your “Welcome” documentation

The welcome documentation is usually an email that is sent to a new client containing server and account access information. It’s important to cover your bases to avoid ending up with confused users that have no other avenue but to ask you for help – something that tends to be frustrating for a new user. Your welcome email should not be wordy, but rather bulleted and easy to read, and separated into sections. It should contain any information your users needs to access their account and server, steps to get started, and how to find help.

Use video tutorials

Sites like Demo Demo provide flash tutorials for common control panel software, that can be branded to your company and used in your support center. Making it known to your customers that flash tutorials are available to explain the procedures for common tasks may prevent them from contacting you.

Establish a knowledge base

A knowledge base is generally used by hosting providers to provide information to address common questions and problems encountered by customers. If you’re seeing a common question being risen by your users, consider making the answer to that question more visible by adding it to a knowledge base full of FAQs, or adding it to your welcome documentation.

Don’t do anything that provokes a response

It should be expected that changes and upgrades will need to take place during the life of a user’s account. However, unless you’ve planned for the worse, don’t make changes that your customers will notice and likely contact you about unless you’ve notified them first. If you’re making a change that may affect users, make sure your users know how the change can affect them and what steps to take if they have a problem. It’s not recommended to play fast and loose with items that will attract user attention in a negative light, so plan your upgrades and changes accordingly.

Be open

Set up a blog or status site that your customers will know to check if they are experiencing a problem. For example, Dreamhost has a website their customers can access to find out about outages or problems, thus preventing them from contacting the customer support center to find out what’s going on. Customers tend to appreciate more transparency when it comes to problems that can affect their site.

Test, test, test

It should go without saying that you should not deploy changes on your hosting servers without thoroughly testing them first.

Keep an eye out

If you are not monitoring your network, you’re a step behind from even the worst of the hosting providers out there. You should be monitoring anything that could cause an interruption in service, as your customers should not know about downtime before you do. Knowing when a problem will happen before it does will easily prevent problems that can result in thousands of dollars in losses and customer support costs.

Be responsive

If you see a problem that is continually affecting multiple clients, do something about it. Sites getting hacked? Consider implementing a solution to block the attacks and issuing an advisor so your customers know you are looking out for them. Hosting servers are in constant need of maintenance to make sure they are running quickly and securely.

Get it right the first time

Anyone that manages a support center will know that each response, phone call, chat, and email costs money. Addressing your customers’ requests and problems correctly and thoroughly the first time will limit your follow ups.

10 Free Monitoring Solutions to Consider

Vanessa — Sun, 17 Jan 2010 21:54:39 +0000

Server and network monitoring can be crucial to a host’s success. I mean, how embarrassing is it when your customers are aware of downtime before you are? You don’t have to pay big bucks or spend loads of time setting up monitoring for your server. We’ve compiled a list of free monitoring solutions you can use to guarantee minimal downtime for your users, and show customers how reliable your service is!

Monitoring Software

With a software option, you’d basically be setting up a server to act as a monitor, or installing software on your PC. Here are some free and open-source software solutions that we’ve used:

Nagios

Nagios is considered one of the best free server/network monitoring tools in the industry. It’s highly customizable and hundreds of plugins are available for it, not to mention that you can easily write your own plugins as well. The only downfall is that the setup can be tricky, and for most setups you need to install the nagios client (NRPE) on the monitored server.

Munin

Munin is a plug and play monitoring software mostly for network performance analysis. On a cPanel server, you can install this easily via WHM > Plugins.

Monitorix

Monitorix is a free, lightweight monitoring application similar to Nagios and Munin

PHP ServerMon

Monitors multiple services across multiple servers, allowing each to have its own custom notification settings.

Server Monitor

PHP-based monitoring software allowing monitoring for multiple ports on a server, and provides details uptime reports

Here is a nice list of a few more: http://sixrevisions.com/tools/10-free-server-network-monitoring-tools-that-kick-ass/

Hosted Solutions

A hosted monitoring solution is a service offered and maintained by another provider, so you don’t have any software to install or configure. You’d generally sign up with the provider and use their control panel to manage your monitored sites. Here are the ones we’ve tested and recommend:

mon.itor.us

Mon.itor.us is a relatively new monitoring service that promises FREE monitoring forever, for external and internal hosts. When you sign up, you get free access to reports and uptime statistics, as well as widgets you can add to your site. At the time this article was written, this service is still in beta but is rapidly improving and is considered very reliable.

247WebMonitoring

This is a 100% free monitoring service that provides a wide range of flexible features for up to 5 sites at intervals of 15, 30, and 60 minutes. Features include content monitoring, pie charts, email/SMS notifications, maintenance mode, and an easy to use control panel. Site also includes a demo showing the service’s easy of use.

SiteUptime

The free plan provides monitoring for one site at 30 or 60-minute intervals for HTTP, POP3, SMTP, and FTP, from multiple locations. Low-cost upgrade options are also available: http://www.siteuptime.com/compare.php

Pingdom

The free plan includes monitoring for one site and up to 20 SMS alerts, with free unlimited email alerts.

Uptime Spy

A more advanced monitoring service that will monitor an unlimited number of resources from several geographic locations at 1,5,15,30, and 60-minute intervals. Features include advanced reporting and statistics, and unlimited notifications.

11 Ways to Free Up Disk Space on a cPanel Server

Vanessa — Sat, 16 Jan 2010 19:05:00 +0000

I’m sure that most of you have been to the point where one or more of your servers start to fill up as you get more customers. The server’s performing just fine, but there’s one problem…you’re out of disk space! Here are a few simple tricks to freeing up disk space on your cPanel server to help maximize your server’s potential.

1) Delete user cPanel and Fantastsico backups

If you have the backup feature in cPanel enabled, chances are your users are storing the backups on the server instead of downloading and removing them. On larger servers, this can account for a lot of disk space usage. You may want to consider warning your users ahead of time that backups will automatically be removed from the server after a certain period of time or on certain dates. You can mass-delete all user cPanel backups on the server with this command:

for user in `/bin/ls -A /var/cpanel/users` ; do rm -fv /home/$user/backup-*$user.tar.gz ; done

To remove Fantastico backups:

rm -rfv /home/*/fantastico_backups

2) Move your backups offsite

Similarly to above, if you’re using the cPanel Backup System and are storing your backups locally on the server, you could be using twice as much space as you need to. Consider mounting a backup server to your hosting server and storing the backups there (there is an option to mount external media in WHM > Configure Backups) or using an alternate method of backing up your server that doesn’t involve storing the backups locally. While local backups may be convenient at times, they tend to be useless when a server failure occurs.

3) Delete cPanel File Manager temp files

When users upload files in File Manager within cPanel, File Manager creates a temp file that may or may not get removed upon upload. You can remove these files using this command:

rm -fv /home/*/tmp/Cpanel_*

4) Move or archive logs

Most of the server’s logs are stored in /var/log, which can get rather large on more populated servers. You can change the length of time and frequency of the log rotation in /etc/logrotate.conf, and enable compression to save additional space (at the expense of CPU when the logs are being gzipped). If you want older logs, consider creating a cron job to periodically transfer them to a backup or log server so they aren’t taking up space on your hosting server.

5) Remove cPanel update archives

Cpanel and EasyApache updates tend to leave behind files that you probably don’t need. The following can be deleted or moved to a backup server to free up a little bit of space:

/usr/local/apache.backup*

/home/cpeasyapache (actual name may vary depending on cpanel version)

6) Clean up Yum files

Yum updates leave package cache files on the server. You can clean up all unneeded yum files by running:

yum clean all

7) Remove pure-ftp partials

When your users upload files to the server via FTP when your server runs pureFTP as an FTP daemon, the FTP server creates temporary files starting with .pureftpd-upload* that get renamed the the actual filename when the upload completes. If the upload doesn’t complete, these files are left on the server. You can find and delete these by running:

locate .pureftpd-upload | xargs rm -fv

*If you don’t run an updatedb regularly, you might want to do so before running this command

8) Decrease the reserved disk space

By default, Linux reserves 5% of the disk space from each partition for the root user, so root can still log in even if the disk is full. You may have noticed when running a df that you may be using 900GB out of a 1TB drive, but only have 50GB available…that’s because the other 50GB is reserved.

For larger drives, you really don’t need the whole 5%. I would recommend setting this value down to 2500 blocks so you can utilize more of the disk space. You can do this with tune2fs:

tune2fs -r 2500 /dev/sda1

You’ll want to probably man the tune2fs command before you use it for other options on setting the reserved space for your partitions.

9) Remove unneeded accounts

If you have a larger churn rate you probably have some user accounts laying around on your server that you don’t need. Check out WHM > List Suspended Accounts (or ls /var/cpanel/suspended) and look for suspended accounts that you may be able to remove from the server to free up space. You can terminate accounts in WHM > Terminate an Account or using the command /scripts/killacct (y/n indicating whether to save the DNS records)

10) Check for contrabands

As a hosting provider you should have a Terms of Service that specifically tells your customers what they can (or rather cannot) store on your server. Most hosts have specific rules about the hosting of non-website-related backups and copyrighted material, but don’t pro actively scan their servers for it. It wouldn’t hurt to run a few locate commands to find common files associated with copyright violations, like .mp3, .avi, .exe, etc, and have your customers remove them from the server. I once cleared over 300Gb of space on a server just by having customers remove contraband files from the server. On top of that, you’re also preserving the integrity of your business from a legal standpoint.

11) Consider a larger server

Some of your customers may have a legitimate need for large amount of disk space, and therefore you may be unable to keep the disk space usage on your server at a reasonable level. A lot of hosting providers have alternate servers that are more “low key” but have huge disk storage volumes to accommodate customers that have larger sites. You might want to consider investing in a server that will be less populated and only the users that occupy a large amount of space.