RAID for Better Performance

RAID stands for Redundant Array of Inexpensive Disks. It’s used to provide fault-tolerance, better performance, or both, to the hard disk storage system, and is therefore used mostly in network servers.

There are several RAID levels, and you’ll need two or more drives depending upon the level you choose to implement. The most common ones are RAID-0, 3, and 5. RAID 0 provides data striping, which spreads out files across multiple disks to offer faster access. This is meant to improve performance. RAID 3 is similar to RAID-0, except that it requires an additional disk for storing error correction data. This provides better performance and fault tolerance. Finally, RAID-5 is the most popular RAID implementation. It provides data striping and error correction, which gives both better performance and fault tolerance. You’ll need at least three hard drives for RAID 5.

RAID can be implemented with both SCSI as well as ATA hard drives, but you can find RAID cards for both. We’ll focus on SCSI RAID here. For implementing RAID, you first need a RAID card, which fits into a PCI slot on your server. We used 64-bit PCI RAID card, the Adaptec ATA 3000S. A 64-bit PCI card is longer than the ordinary 32-bit counterparts found in most PCs. Most server-level machines today have two or more 64-bit PCI slots. Plug-in the RAID card and the SCSI drives. You’ll need a SCSI cable that can support the number of hard drives you intend to use. Connect the SCSI drives with the cable to the RAID controller card.

This RAID card has its own BIOS that lets you configure the hard drives for a RAID level. This way, the RAID will not depend upon the OS you install on it, as it will be configured before the OS loads up. You can access the RAID BIOS by pressing CTRL+A. This will display the RAID-card controller information, and the number of drives connected to your server. On the other right side window panel it shows the parameter for the corresponding items in the left side window panel, you can navigate between the window panels by TAB key.

Now select the RAID controller from the left window panel, and select RAID from the menu bar by pressing (ALT+R) and select ‘create’ from the menu. This will open a small window, where you need to select the type of RAID you need set from the following options ‘RAID (0), RAID (1), RAID-5’. We chose RAID—5 as we had three SCSI hard drives. You can change the stripe size from here only.

We used the default size of 64 kB. Once you select ok, a small window will open on the left panel showing you all the SCSI drive connected with the RAID controller, select all of them by pressing space bar on each, and select the done button moving to it with the TAB key and press enter. This will create a disk array with RAID-5 in a second. It will ask you to save the setting press ok to save it. And your RAID-5 is ready to
use.