Interface Cards & Controllers

What You Need to Know About Nested RAID Levels

In addition to the standard RAID levels of 0-6, there are also nested or hybrid levels. Nested levels combine two or more standard RAIDs to improve performance or offer better protection against data loss. These levels are multiple arrays of a particular type that are grouped together in the form of a different type of array.

In this article, we'll take a look at some of the more common nested RAID levels and some of the features they offer.

 

RAID 0+1

RAID 0+1 is a combination of standard levels 0 and 1. This level requires a minimum of 3 drives with 4 drives being the most common setup. It allows you to create a mirror image of the data as with RAID 1 and share the data between drives as with RAID 0.  The best way to describe it is as a combination of two separate 0 arrays that are combined together to form a level 1 array.

The 0+1 configuration is somewhat less fault tolerant than some other levels and two simultaneous disk failures would crash the system. For this reason, businesses and people with critical data tend to opt for different setups.

 

RAID 10

The configuration of a RAID 10 is the reverse of a RAID 0+1 in that it can be conceptualized as two separate level 1 arrays that are combined to form a single RAID 0 array. It requires a minimum of four hard drives to implement.

This type of configuration allows for very fast performance when reading data since it minimizes the amount of seeking required to locate any given data element. The downside is that if a failed drive in the array is not replaced, it can create a single point of failure which can crash the entire system. One way to get around this is to add a "hot spare" drive, that is, a hard disk drive that is not used in the array until one of the working drives crashes. When one drive fails, the hot spare drive automatically takes its place in the array. 

 

RAID 30

RAID 30 is a combination of RAID 3 and RAID 0. It makes use of striping, which allocates separate data segments to different disks in the system, and a dedicated parity disk to store information that allows data to be reconstructed in the event of a drive failure.

 

RAID 50

RAID 50 arrays combine block level striping from RAID 0 and distributed parity from RAID 5. This requires at least 6 drives for implementation and is essentially 3 level 5 sets combined as a RAID 0 array. This type of array can tolerate a failure from any one of the drives in the level 5 arrays without losing any data. Once a drive has failed, though, it must be replaced as soon as possible as it creates a single failure point for the rest of the array.

 

RAID 51

RAID 51 consists of two RAID 5 arrays combined as a single RAID 1. This configuration has a high level of fault tolerance, all the disks in one of the level 5 arrays and one in the other can fail before there is any loss of data.

 

RAID 60

RAID 60 requires at least 8 hard drives and is essentially two separate RAID 6 arrays combined as a RAID 0. Up to two disks on each set could fail before you would lose any data. This setup increases both storage capacity and performance compared to a RAID 6 array. These arrays tend to be slightly slower than RAID 50 but they offer better data security. 

 

RAID 100

This configuration is essentially two RAID 10s combined as a RAID 0 array. IN many cases the top level 0 array is implemented as a logical drive using software rather than a physical disk drive. This is usually the best choice for very large databases, giving you better read performance while lessening the load on individual controllers.  

 

There are many other less common forms of nested RAID arrays, but these are the most usual setups. Each if these configurations comes with their own advantages and disadvantages. The RAID level that is best for you or your business depends on your own particular requirements. Some levels provide better protection against data loss, while others offer superior performance in either reading or writing data, or both. The decision comes down to how critical your data is for you or your business and whether performance or data security is the most important criteria for you.

About the Author

Data Recovery Specialist

Warrior Manual

Warriors are the most flexible classes in World of Warcraft. This warrior guide will check out all of the issues with the warrior and ways in which make use of your character in Player Vs Environment and PvP conditions. And how to get a warrior to level 80 quickly.

Since you can have dual talent builds and don’t have to spend all your gold to re-spec your warrior, the class is a lot more fun to play. In Particular tanks ended up really distressed that they were almost can not put up damage or perform by themselves other than raids.

Now you can switch back and forth to the the Fury or Arms build easily (and for FREE).

I recommend you to gather both offensive and defensive gear if you plan to both play alone (farm or play PvP) and as a tank in a raid group.

The first talent tree I want to talk about in this warrior guide is the Protection tree. These talents are what make a warrior a great tank. There’s nothing else to say about protection talents, really. They improve your defensive and in combination with gear that provides you endurance you become the center of each and every raid group.

Just really don't make the miscalculation to consider you may as well be considered a “fortress” in Player Vs Player battle. Protection seriously isn't possible for Player Vs Player, because the opposition only will dismiss you.

Now, the next build to speak about will be the Arms build. This one is wonderful for leveling and Player Vs Player objectives. It targets on huge 2handed weapon. It should be genuinely slow-moving in assault speed but provide a large impairment with all of its sluggish swing motion. You will get plenty of talents which gives you an free, instant attack to deal this high damage.

Mortal Hit can also be fantastic in PvP because you can basically disable restorative healing to the targets for a while.

Fury stands out as the third skill build in my warrior tutorial. It’s also viable for leveling but best in PvE when it comes to DPS. It is possible to dual- wield 1h weapons and also two 2h items down the line! The high assault rate is most effective supported by using a excessive attack ranking to make certain you really don't spend any swings.

I hope you liked my warrior guide and got some valuation as a result. Enjoy yourself playing your warrior and be sure to test out every single build to discover which meets you the greatest.

What model gun did Obama use when he single-handedly raided the compound and killed Bin Laden?

Had to be something small enough to allow him to pilot the chopper....

Resident Evil: Revelations boasts $50 price, and that's without the Circle Pad (feeds.joystiq)

What do you do when your competition is busy undercutting your portable game
offerings with $1 apps? If you're Nintendo and Capcom, your strategy is to
aggressively run in the opposite direction (coincidentally, that is our
favorite Resident Evil strategy). Next year's _Resident Evil: Revelations_ is
an impressive, console-esque experience that is notably as expensive as a
console game. GameStop lists the 3DS title for $50, and that doesn't include
the $10 Circle Pad attachment.

"_Resident Evil Revelations_ is an all new Resident Evil title with over 20
hours of gameplay, and cutscenes beautifully rendered in fear-inducing 3D," a
Capcom spokesperson told Kotaku via email. "A true console experience on a
handheld device, _Resident Evil Revelations_ is an epic title that offers both
a single-player campaign for that classic survival horror gaming experience,
and an additional RAID mode that can be played cooperatively or single player.
To handle all of that data Resident Evil Revelations requires a 4GB cartridge,
resulting in a higher price point."

The larger 4GB cartridge brings back (mostly bad) memories of cartridge-based
consoles past: the Genesis, Super Nintendo, Nintendo 64. Bigger experiences
require bigger storage and, in turn, a bigger price tag. Bringing ...

feeds.joystiq

Proxmox VE with DRBD on a single RAID Volume (research only!)