When you have to decide between Raid 0 vs Raid 1 for your disk arrays, there are many factors that need to be considered. The performance level which is excellent for certain applications may not be good enough for others. Therefore, the best option is to evaluate what exactly your needs are and what the requirements of your applications are.
You also need to determine what your response time will be and what reliability add-ons will help your applications. There are several advantages of raid 0 vs raid 1 depending on how your data needs are handled.
What is RAID?
RAID (redundant array of independent disks) is the way to store the same data in various locations on different hard disks. RAID is a technology used to boost data storage capacity and/or reliability.
The two main types of disk arrays available are: raid 0 and raid 1. Others raids are Raid 5 and Raid 6.
What is RAID 0 (Disk Striping)?
RAID 0 is a mechanism by which data blocks, such as hard drives or Solid-State drives (SSDs) are broken up into blocks to distribute data blocks around a range of storage equipment in interchangeable clusters of individual discs (RAID).
What is RAID 1 (Disk Mirroring)?
Disk mirroring, also known as RAID 1, is the replication of data to two or more disks. When a drive fails, the drive uses a drive for data recovery and continuous operation either by data drive or mirror drive. A RAID 1 array needs at least 2 drives.
What is RAID 5 (Striping with Parity)?
The most popular secure level of RAID is RAID 5. It takes at least three drives, but can run with up to 16 drives. Data blocks are stretched across drives and all block data are tested for parity on one disc.
What is RAID 6 (Striping with Double Parity)?
RAID 6 is the same as RAID 5, but two drives have parity data written. It needs at least four drives and can resist the death of two drives at the same time. There is, of course, very little possibility that two drives fail at precisely the same time. However, it takes time or more than one day to reconstruct the switched drive if a drive in the RAID 5 systems fails and is replaced with a new drive.
What is RAID 10 (Combining Mirroring and Striping)?
The benefits (and drawbacks) of RAID 0 and RAID 1 can be merged in one method. It is a RAID configuration that is nestled or hybrid. It offers security, by using striping through each drive collection to speed data transfer, by mirroring any data in secondary drives.
Which is Better Raid 0 or Raid 1?
RAID 0 stands for Redundant Array of Independent Disk level 0 and RAID 1 stands for Redundant Array of Independent Disk level 1. The main difference between the RAID 0 and RAID 1 is that, In RAID 0 technology, Disk stripping is used. On the other hand, in RAID 1 technology, Disk mirroring is used.
| SL No | RAID 0 | RAID 1 |
|---|---|---|
| 1. | RAID 0 also know as Redundant Array of Independent Disk level 0. | RAID 1 knows as Redundant Array of Independent Disk level 1. |
| 2. | Disc stripping technology is used in RAID 0. | Disk mirroring technology is used in RAID 1. |
| 3. | RAID 0 technology is inexpensive compared to RAID 1. | RAID 1 is costly. |
| 4. | There is no write penalty. | There is write penalty. |
| 5. | Relative storage efficiency of RAID 0 is 100%. | Relative storage efficiency of RAID 1 is 50%. |
| 6. | The write performance of RAID 0 is faster. | The write performance of RAID 1 is slower. |
| 7. | RAID 0 focuses on data accessing speed. | RAID 1 focuses on data availability. |
| 8. | RAID 0 is good at read performance. | RAID 1 is moderate in read performance. |
| 9. | RAID 0 doesn’t have protection. | RAID 1 is much more secure. |
In a nutshell, raid 10 vs raid 01 are just a matter of compatibility and raid 10 provides the best performance. There is no point in having both types if they are not going to be used in a redundant manner. With raid 10 data mirrored across disks in the array, this provides the best of both worlds where the requirements of the application are met and the performance is guaranteed.
Disk drives can get hot; therefore, performance degradation occurs at times when both sets of disks are written at the same time. This is a normal part of operation and is the reason why raid 0 is often considered superior to raid 1. Because the drives are written twice as fast, performance gets much better results. A disk can also spin faster thereby increasing the overall throughput which will make the application run a lot quicker. On the contrary, in raid 1 a failure in one drive can lead to failure in the others also which can seriously impact the speed performance of the entire array. Hence, the performance gets better when raid ratio is more than 2.
It is true that these disadvantages outweigh the advantages of raid level storage arrays. But it is still important to understand how disk arrays work and their limitations. By understanding some of the drawbacks you can use raid balance to gain an upper hand in selecting the best storage medium for your needs. The three main limitations of raid disk usage are: write head collision, write fragmentation and lost parity bits.
Write head collision is the most serious disadvantage of using disk failure. When a drive writes over a bad sector or over a bad disk, there is always a possibility that the information will be overwritten by new data. On a regular raid array there would be only one failure per stripe but when there are two disks in a multi-RAID setup the probability of two disk failures increases significantly.
So if a multi-RAID setup has two raid levels the probability of two disk failure increases dramatically. You have to take into account the probability of the two disk failures when considering a disk failure scenario.
Write fragmentation occurs due to the random write operations performed by raid arrays. In such a case the operating system cannot assure that the same information is not overwritten on different disks. Such an occurrence may lead to information loss or corruption. In order to avoid this kind of operation you have to configure the stripe widths to be much wider in your raid array than the usual default of 16 disk spaces.
Write-through is a second major disadvantage of raid arrays. It occurs when a single disk fails or heads are damaged and the remaining ones continue to operate. In such case you have to wait till the other disk is repaired so as to complete the write operation on the failed disk. If the raid array has been configured to utilize striped data writes then the write-through probability is better.
There are some minor disadvantages of raid data management i.e. performance degradation due to fewer reads and writes, increased access time, lower disk space utilization, reduced allocation speeds and higher power utilization. However, these disadvantages occur at the interface level and are not visible to administrators.
The data loss from disk mirroring can easily be prevented by using quality drives. There are some third party technologies like the SMART feature which can detect failure on time and repair it automatically but you have to pay for this.
