Guide to Server Colocation

This colocation guide is written mainly with our colocation services in mind however it provides information which will hopefully be of general use.

All colocated dedicated servers run "headless." This means without the use of a keyboard or monitor attached. Therefore you will need to ensure that the servers gets past the BIOS screen and boots the desired kernel without having to press any keys. It might be possible to set the BIOS on your dedicated server to stop on "no errors."

If your are running Linux the kernel you will need to ensure the correct kernel is booted without intervention. This is usually determined by the configuration on /etc/grub.conf if the GRUB boot loader is used, or /etc/lilo.conf if the LILO boot loader is used. After any changes have been made to the LILO configuration remember to run "/sbin/lilo -v" and ensure there are no errors.

Also make sure the kernel "works" properly with the hardware. This is especially true if have compiled the kernel yourself or are using specialist hardware.

Most colocation facilities provide an auto power cycler from a web interface. However this can fail if the machine does not auto power back up (requiring the intervention of a techie). Most server BIOS's are equipped with either "OFF", "LAST STATE" or "ALWAYS ON". In this case you will require "ALWAYS ON." it is possible to hack cheaper ATX motherboards to be "ALWAYS ON" but it is better to consider a more expensive motherboard.

Make sure you configure the network addresses, DNS server and gateways properly prior to delivery of the dedicated server. This information will have been provided in advance by the colocation provider. Also make sure you can get back into the server remotely by having the SSHD daemon running (telnet is not secure).

OpenSSH is shipped with all the main Linux distributions. You might wish to consider configuring SSH (usually done in /etc/sshd/sshd_config) to work with Protocol2 only, disable root logins (or only allow public key exchanges with the `without-password` option) and to turn off X11 forwarding as this is not required on a production server.

Many servers have multiple ethernet connectors, so it an be helpful, if you are not using the second interface to either mask it off with tape or label the correct ethernet device.

This is sometimes called "out of band" management. Quite often a colocation provider will have a serial terminal on site. This is basically a server itself but with loads of serial ports. This enables you to connect to your server if the network has failed to your server for any reason.

The most common serial port settings are 9600 8n1 (we do not recommend running it a faster speed). If you are running a Red Hat Linux server serial console access is usually configured in "/etc/inittab." Try inserting the line below:

co:23456:respawn:/sbin/agetty ttyS0 9600 vt100

Servers run pretty hot mainly due to modern processors. Even in a fully air conditioned environment. It will pay you look into cooling. A lot will depend on rack density however this is one more reason why you should consider a rack optimised server, as the air cooling in a colocated environment should have been taken into consideration. You can also familiarise with the chipset architecture of your motherboard and consider setting up "sensors." You can then monitor the temperature of your CPU and motherboard and graph it using MRTG.

You may wish to consider disc or hard drive redundancy. Although the "MTF" or Mean Time to Failure" quoted by hard drive manufacturers is impressive, hard drive failure, especially IDE failure happens depressingly often. With advent of S-ATA drives there is really no excuse, expecially if your are on a budget. You should consider cheap S-ATA drives (if you cannot afford SCSI) with Linux software RAID. Modern Linux distributions come with tools to administer and monitor the performance of software RAID arrays.

It can be helpful to duty technicians if all the main power lights are working. The power light, hard drive activity light and network light can be very useful. It goes without saying that the server should be correctly labelled at the front with it's hostname and IP address so it can be identified quickly.

If you want to explore any further idea's discussed in the above or find any of it confusing do not hesitate to get in touch at admin (at) weycrest.com. You can find out more about our colocation pricing on our colocation page.