Does My RAID Server Need a BBU?

raid bbu

“What is a BBU for RAID and do I need one?” This question comes up often for HostDime technicians, so let’s examine the purpose of a BBU, which stands for “battery backup unit.” This awesome device protects and maintains the cached data that is on your server’s raid card. A BBU is essentially a data fail-safe. Let’s dive into the specifics.

Why a RAID Server Needs BBU

Here’s a scary scenario: say for one reason or another, your dedicated server loses power before changes have left the cache and are committed to disk. You are now left with an non-completed query, or worse, corrupted data.

The battery backup unit allows the RAID card to remember what hasn’t yet been synced to disk. The BBU can provide enough backup power to preserve the data for up to 72 hours without power. When the machine powers back up, the BBU will write the cache contents on the disk. All contents on the RAID card buffer become unrecoverable if there is no BBU. The worst part is, you may not even know what files were damaged or corrupted.

If your “write cache” option is set to “write through” or “off”, then you should be fine without a BBU on your raid card. The downside to having “write cache” turned off is RAID performance will be sub-optimal. Many RAID cards will have the write cache setting “on” only if the BBU is installed. This is very important for users who frequently save their database from certain types of corruption or need high data integrity.

RAID Servers with BBU from HostDime

HostDime techs created a RAID calculator that compares and configures RAID options and drive sizes to expand on your server’s performance. Simply drag and drop the drives into the slots to see each RAID’s description, disk capacity, disk input/output performance, minimum number of disks, fault tolerance, and more.

raid calculator

HostDime is one of the few infrastructure providers in the world that not only offers BBU for RAID controllers, but has technicians checking the battery constantly. HostDime uses MegaRAID’s intelligent battery backup unit that preserves data integrity for 72 hours.

If you are a current client and have a raid card, contact us to add a MegaRAID BBU for $20 a month! If you are not, take a look at our bare metal servers and customize your server to your specific data protection specifications.

raid servers

For custom configurations and any more questions you may have, feel free to contact us directly.

What is the Best RAID Configuration for Your Server?


Jared Smith is HostDime’s SEO & Content Strategist.