Setting up on physical servers
Note: You only need one of the three setup methods!
Setup, Method 2 – Setting up on physical servers
To set up Gluster on physical servers, we recommend two servers of very modest specifications (2 CPU’s, 2GB of RAM, 1GBE). Since we are dealing with physical hardware here, keep in mind, what we are showing here is for testing purposes. In the end, remember that forces beyond your control (aka, your bosses’ boss...) can force you to take that the “just for a quick test” environment right into production, despite your kicking and screaming against it. To prevent this, it can be a good idea to deploy your test environment as much as possible the same way you would to a production environment (in case it becomes one, as mentioned above). That being said, here is a reminder of some of the best practices we mentioned before:
- Make sure DNS and NTP are setup, correct, and working
- If you have access to a backend storage network, use it! 10GBE or InfiniBand are great if you have access to them, but even a 1GBE backbone can help you get the most out of your deployment. Make sure that the interfaces you are going to use are also in DNS since we will be using the hostnames when we deploy Gluster
- When it comes to disks, the more the merrier. Although you could technically fake things out with a single disk, there would be performance issues as soon as you tried to do any real work on the servers
With the explosion of commodity hardware, you don’t need to be a hardware expert these days to deploy a server. Although this is generally a good thing, it also means that paying attention to some important, performance impacting BIOS settings is commonly ignored. A few things I have seen cause issues when people didn't know to look for them:
- Most manufacturers enable power saving mode by default. This is a great idea for servers that do not have high-performance requirements. For the average storage server, the performance impact of the power savings is not a reasonable tradeoff
- Newer motherboards and processors have lots of nifty features! Enhancements in virtualization, newer ways of doing predictive algorithms and NUMA are just a few to mention. To be safe, many manufactures ship hardware with settings meant to work with as massive a variety of workloads and configurations as they have customers. One issue you could face is when you set up that blazing fast 10GBE card you were so thrilled about installing? In many cases, it would end up being crippled by a default 1x speed put in place on the PCI-E bus by the motherboard.
Thankfully, most manufacturers show all the BIOS settings, including the defaults, right in the manual. It only takes a few minutes to download, and you don’t even have to power off the server unless you need to make changes. More and more boards include the functionality to make changes in the BIOS on the fly without even powering the box off. One word of caution of course, is don’t go too crazy. Fretting over each tiny little detail and setting is usually not worth the time, and the more changes you make, the more you need to document and implement later. Try to find the happy balance between time spent managing the hardware (which ideally should be as close to zero after you setup initially) and the expected gains you get back from it.
Finally, remember that some hardware really is better than others. Without pointing fingers anywhere specifically, it is often true that onboard components are not as robust as add-ons. As a general rule, you can safely delegate the onboard hardware to things like management network for the NIC’s, and for installing the OS onto a SATA drive. At least twice a year you should check the manufacturer's website for bulletins about your hardware. Critical performance issues are often resolved with a simple driver or firmware update. As often as not, these updates affect the two most critical pieces of hardware on a machine you want to use for networked storage - the RAID controller and the NIC's.
Once you have setup the servers and installed the OS, you are ready to move on to the install section.