Disk failure is the most frequent type of hardware failures. With RAID, your server can survive a disk failure. Depending on the number of disks and RAID level, several disk failures at the same time can take place, without loss of data.
RAID should not be considered as back-up, but merely a layer of redundancy for hardware failures.
Most of our server configurations include a hardware RAID controller, which comes pre-configured by EasySpeedy. We choose RAID level 1 or 10, depending on the amount and types of disk drives.
In the event of a disk failure, you can submit a support ticket to have our on-site technical staff replace the disk. This is of course free of charge.
The idea behind RAID (Redundant Array of Independent Disks), is to improve performance and reliability and protect your data if possible disk failures occurs.
RAID basically takes multiple disk drives and collects them in a logical volume, allowing them to be used as one disk drive, with benefits depending on the scheme/level of RAID being used.
For servers with multiple disks, EasySpeedy uses disks with different production batches and manufacturers wherever possible, to minimize the risk of multiple disk failures at the same time.
RAID should not be considered an equivalent to back-up.
There are many possible RAID configuration. Review the two most common configurations in our server environment:
RAID 1 (mirror)
A mirrored array, writes data to two or more disks drives simultaneously, resulting in a level of redundancy. In this type of array, the storage capacity is limited to the size of a single physical disk (the smallest one) in the array. There is a small cost of write performance, as the same data needs to be written to all disks in the array. However the great advantage of mirroring is, when it comes to data integrity and security against disk failure. The array provides fault tolerance from disk errors and failures, and continues to operate as long as at least one drive in the array is functioning.
RAID 1+0 (stripe of mirrors)
Sometimes shortened to RAID 10, RAID 1+0 is a combination of two different RAID levels: mirroring (RAID 1) and striping (RAID 0). With RAID 1+0, you first mirror the disks, and then you lay the stripes on top of the mirrored disks.
In terms of fault tolerance, each of the mirrored pairs is a logical disk, so you can lose one member of each pair and the stripe will still work. RAID 1+0 is our preferred choice for servers with four or more disk drives.
Software or Hardware RAID
If your server is without a hardware controller, don't worry, most operating systems let you configure software RAID.
The main advantages of using hardware RAID controllers can be read and write cache for performance, and a uniform configuration interface regardless which operating system you're using.
Software RAID however, is configured from the operating system which means that the same RAID array will not necessarily work from within a different operating system. Software RAID however, usually includes all the necessary tools to configure and monitor the array from within the operating system.
Software RAID can be configured with most operating systems, and in most cases this can be configured manually during install time. Our automated install system, gives you the option to pause the installers during the partitioning setup step, to let you perform a manual configuration.
Hardware RAID controllers
Configuring a RAID volume depends on which RAID controller, if any, is used.
Hardware RAID controllers are usually configured by entering the RAID BIOS configuration utility during controller initialization at boot time.
Below is a table of the different server and RAID controller combinations we have:
|Manufacturer||Model||RAID Controller||RAID Levels||Management Utility|
|Sun Microsystems||Fire X2100 M2||Software||0 / 1|
|Fire X2200 M2*||LSI SAS 1064 RAID HBA||0 / 1|
|Sun StorageTek SAS RAID HBA (SGXPCIESAS-R-INT-Z)||0 / 1 / 5 /|
10 / 50
|LSI SAS 1064 RAID HBA||0 / 1|
|LSI MegaRAID SAS 2208||0 / 1 / 5 / 6 / 00 /|
10 / 50 / 60
|LSI SASII 2008||0 / 1 / 10|
* Only on specific configurations. Create a support ticket if in doubt.
LSI SAS 1064 RAID HBA
This controller is used in some of our Sun Microsystems Fire X2200 M2 server configurations and in some Fujitsu Blade servers.
The LSI SAS 1064 chipset is a very widely used and extremely well supported HBA. It supports configuring RAID arrays from the controller BIOS but also works like a HBA (Host Bus Adapter). This means you are free to choose from the onboard RAID functionality or software RAID.
The controller is very well suited for configurations which allows for only two disk drives.
You can access the controller configuration BIOS when the controller initializes during boot, by pressing CTRL+C.
RAID 1 (mirror) is referred to as IM inside the controller BIOS configuration utility.
Sun StorageTek SAS RAID HBA
The Sun StorageTek SAS RAID HBA Internal (SGXPCIESAS-R-INT-Z) is a full blown high performance SAS RAID controller, with 256 MB on-board battery backed cache.
You can access the controller configuration BIOS when the controller initializes during boot, by pressing CTRL+A.
We initialize the servers by creating either a RAID 1 or RAID 1+0 (10) array (depending on the number of disk drives) with default options and write cache enabled (with battery).
You are free to delete the RAID array and create one with your own preferences. This controller also allows for hot swapping of disks.
The controller does not support JBOD, but you can configure each disk as RAID0 to accomplish a similar scenario to e.g. allow the use of Software RAID if preferred.
LSI MegaRAID SAS 2208 (D3116)
The LSI MegaRAID SAS 2208 RAID controller is a full blown high performance SAS RAID controller, with 1 GB on-board cache. This controller also allows for hot swapping of disks.
You can access the controller configuration BIOS during boot, or you can configure RAID using our Recovery Tool, see MegaCli.
We do not pre-configure RAID on this type controller.
If you prefer ou can configure each disk as RAID0 to accomplish a similar scenario to e.g. allow the use of Software RAID if preferred.
Knowing how to manage your servers RAID controller is an important part of server operations, ensuring your servers RAID array is created and operating as wanted, and knowing when a disk drive has failed and needs replacing.
We advise that you visit the RAID controller BIOS setup to become acquainted with the configuration.
The arcconf CLI management utility is contained in the Sun StorageTek RAID Manager for Linux package, which can be found in the above download links.
|Get version info|
|Get logical device info|
|Get controller info|
|Get physical device info|
|Delete logical volumes|
|Set physical disk to RDY (ready) state|
(0 0 for disk #0, 0 1 for disk #1)
(0 0 for disk #0, 0 1 for disk #1)
|Create logical RAID1 volume|
|Create logical RAID10 volume|
The MegaCLI utility is included with our Recovery Tool. See MegaRAID MegaCLI for more information.