In a hardware raid setup, the drives connect to a raid controller card inserted in a fast pciexpress pcie slot in a motherboard. But with budget favoring the software raid, those wanting optimum performance and. Comparing raid performance at all levels spiceworks. Read performance is identical between all raid types.
Data protection and performance benefits of raid more robust faulttolerant features and increased performance versus softwarebased raid. Also, just did some testing on the latest mlc fusionio cards and we used 1, 2 and 3 in various combinations on the same machine. Mdadm is linux based software that allows you to use the operating system to create and handle raid arrays with ssds or normal hdds. Solutions like zfs can perform better than hardware because they. For example, if you just look at raid1, and you have a crappy controller like the intel matrix, and compare that to the native raid1 software in linux, then the linux version can be 2x faster on reads, in a perfect world, due. Theres a lot of discussion here about pros and cons of various raid levels and we thought we might be able to assist. In this article i will share the steps to configure software raid 5 using three disks but you can use the same method to create software raid 5 array for more than 3 disks based on your requirement. If a disk in the raid 0 system fails the system fails, and all data spread across the disks will be gone.
The comparison of these two competing linux raid offerings were done with two ssds of raid0 and raid1 and then four ssds using raid0, raid1, and raid10 levels. In this article i will share the steps to configure software raid 0 i. The read performance im getting is maxing out around 250 mbs used to be 170 mbs with raid5. The hw raid was a quite expensive usd 800 adaptec sas31205 pci express 12sataport pcie x8 hardware raid card. It has seven modes of operation that pretty much cover any possible task you might use software raid. You can improve performance up to 20% by using the right parameters when you configure the filesystems on your raid devices. Software raid, as you might already know, is usually builtin on your os and unlike a hardware raid, you will need to spend a little extra on a controller card. A redundant array of independent drives or disks, also known as redundant array of inexpensive drives or disks raid is a term for data storage schemes that divide and replicate data among multiple hard drives. Improve software raid speeds on linux posted on june 1, 20 by lucatnt about a week ago i rebuilt my debianbased home server, finally replacing an old pentium 4 pc with a more modern system which has onboard sata ports and gigabit ethernet, what an improvement.
I have written another article with comparison and difference between various raid types using figures including pros and cons of. Note also that the write performance for hardware raid is better. When they said that it is built on top of linux, they mean it. I will explain this in more detail in the upcoming chapters. Compared to independent disk drives, raid 1 logical drives provide improved performance, with twice. The goal of this study is to determine the cheapest reasonably performant solution for a 5spindle software raid configuration using linux as an nfs file server for a home office.
In testing both software and hardware raid performance i employed six. How to improve server performance by io tuning part 1. Increasing the stripe width adds more disks and can improve readwrite performance if the stripe width chunk size is greater than the data size. In hardware raid the algorithms are implemented in a controller card. I have recently noticed that write speed to the raid array is very slow. However, the software raid provided with standard linux distributions was developed without consideration for highspeed block devices resulting in suboptimal. It pro and contributor to our blog, scott alan miller, wrote for us a very detailed analysis of raid performance at various levels from 0, 5, 6, and 10. Raid6 has a high write performance penalty, and a properlysized wb. Speaking of raid levels, raid 45 will never give you good performance, that is comparing to raid0 or raid10. Besides, this raid is only suitable for raid 0 and raid 1. In testing both software and hardware raid performance i employed six 750gb samsung sata drives in three raid configurations 5, 6, and 10. Raid 0 is used to enhance the readwrite performance of large data sets, and to increase logical unit capacity beyond the limits of a single disk device. We demonstrate how beautifully ssd raid arrays can scale. Linux software raid level 0 technique for high performance.
The server has two 1tb disks, in a software raid1 array, using mdadm. Usually, hardware raid has better performance with the advanced raid levels than software raid. It is a way to virtualize multiple, independent hard disk drives into one or more arrays to improve performance, capacity and reliability. It allows user to do both filebyfile and sectorbysector disk clone. The difference is not big between the expensive hw raid controller and linux sw raid.
The write performance is reduced however, as a sequential write involves both drives seeking back and forth between distant parts of the drive. Software raid combines multiple drives into a logical volume through disk management feature provided by operating. Linux software raid has native raid10 capability, and it exposes three possible layout for raid10style array. I have written another article with comparison and difference between various raid types using figures including pros and cons of individual raid types so that you can make an informed decision before choosing a. Normal io includes home directory service, mostlyreadonly large file service e. Does it really make a difference compared to mdadm. The drives used for testing were four ocztoshiba trion 150 120gb ssds.
Raid 1 data is mirrored on each drive, improving read performance and reliability. Data protection and performance benefits of raid more robust faulttolerant features and increased performance versus software based raid. Mdadm pronounced mdadam is a tool for linux for managing software raid devices in linux. Software raid 1 with dissimilar size and performance drives.
Software vs hardware raid performance and cache usage server. You can always increase the speed of linux software raid 0156. The other arrangement is to interleave areas of one disk with the other so that you take the fi. For n disks in the mirror, this could improve performance nfold. A redundant array of inexpensive disks raid allows high levels of storage reliability. For writes, the chunk size does not make a difference, since every write must go. Performance comparison of mdadm raid0 and lvm striped. But if better performance is your goal, it pays to do some shopping. How raid can give your hard drives ssdlike performance. For pure performance the best choice probably is linux md raid, but nowadays i. The real performance numbers closely match the theoretical performance i described earlier. In general, software raid offers very good performance and is relatively easy to maintain. In computer storage, the standard raid levels comprise a basic set of raid redundant array of independent disks configurations that employ the techniques of striping, mirroring, or parity to create large reliable data stores from multiple generalpurpose computer hard disk drives hdds. With software raid, you might actually see better performance with the cfq.
Standard raid levels include raid 0, raid 1, raid 2, raid 4, raid 5, raid 6, raid 10, etc. Within a raid 5 array as there are more drives to share the load the file system will run slower but not as slow as it would in the raid 1 situation and by adding more drives to an array this performance reduction is reduced. Raid 1 will be implemented with at least two disks and always with an even number of disks. When you do raid0 striping you essentially combine the two disks. Monitoring and managing linux software raid prefetch. A lot of software raids performance depends on the. Raid 0, or disk striping, requires at least two disk drives and increases performance by.
It is used to improve disk io performance and reliability of your server or workstation. You should then ask yourself if the software raid found in linux is comprehensive enough for your system. Besides the different raid levels which i cover in the other post there are two main categories of raid to consider. I am the proud user of linux software raid on my home server, but for a proper enterprise system i would try to avoid it. For raid5 linux was 30 % faster 440 mbs vs 340 mbs for reads. Many users just opt for the defaults and dont think about the file system when they install linux. This raid will also provide faulttolerance and improve performance. Raid level comparison table raid data recovery services. Linux software raid mdadm testing is a continuation of the earlier standalone benchmarks. A raid can be deployed using both software and hardware. Is there any performance increase from using the raid supported by the motherboard. I keep hearing that raid 1 is supposed to increase read performance because data is duplexed on both drives.
However, of all the zillions of raid controllers ive worked with ive never seen a raid 1 card improve read performance. But the real question is whether you should use a hardware raid solution or a software raid solution. Raid 0 is bad because it doesnt improve seek time the crux of hd performance and its extremely unreliable. The raid software is what is used to configure the desired raid level of features in an array. Raid0 and raid10,f2 reads are double speed compared to ordinary file system for. Raid arrays with dozens of hard drives are not uncommon for reaching certain performance levels. Finally, while it is almost impossible to justify comparing raid 0 and lvm performance, human nature will push it us to do a comparison. Before raid was raid, software disk mirroring raid 1 was a huge profit generator for system vendors, who sold it as an addon to their operating systems. To introduce users a freeware for raid array clone is exactly the major reason for writing this article. It appears as though raid 0 offers a bit better throughput performance than lvm, particularly at the very small record sizes. For each raid 5 stripe there is a parity data block, and the parity data blocks are spread out over all disks in a roundrobin fashion.
When i migrated simply moved the mirrored disks over, from the old server ubuntu 9. Mdadm is linux based software that allows you to use the operating system to. Must wait for the write to occur to all of the disks. We will investigate the performance of the various cards in a raid 1 configuration in the same way that we investigated the performance of the cards in a raid 0 array. While the first aspect tells us if the hard disk drive performance really increases with raid0, the second aspect will tell us if this increase in disk performance if any will be translated into. Speed up linux software raid various command line tips to increase the speed of. The theoretical and real performance of raid 10 server. Raid functions are performed on a microprocessor located on the external raid controller independent of the host. How to upgrade your workstation with highcapacity raid. It can either be performed in the host servers cpu software raid, or in an external cpu hardware raid. Software raid how to optimize software raid on linux using.
Software vs hardware raid nixcraft linux tips, hacks. Soft possibly the longest running battle in raid circles is which is faster, hardware raid or software raid. Raid0 with 2 drives came in second and raid0 with 3 drives was the fastest by quite a margin 30 to 40% faster at most db ops than any nonraid0 config. Raid 0 increases performance by allowing read and writes to be performed concurrently. Ive been working with server based raid controllers for a long time with pretty much all raid levels. Ive personally seen a software raid 1 beat an lsi hardware raid 1 that was using the same drives. Lets start the hardware vs software raid battle with the hardware side. It has the redundancy of a raid 1, and the performance of a raid 0 system, but you need four disks and only get the capacity of two. The first raid cloning software is aomei backupper. A raid 1 logical drive is built from two disk drives, where one disk drive is a mirror of the other the same data is stored on each disk drive. Raid 5 has a well known performance issues when writing data. Different types of raid controllers support different raid levels.
The trivial way and nonperformance enhancing is to arrange one disk after the other. Performance comparison between raid1 and raid 5 solutions. These layouts have different performance characteristics, so it is important to choose the right layout for your workload. Raid can be designed to provide increased data reliability or increased io performance, though one goal may compromise the other. The most common types are raid 0 striping, raid 1 mirroring and its variants, raid 5 distributed. Software raid how to optimize software raid on linux. To build our raid 5 array we decided upon a stripe size of 128kb, as this stripe size allowed for good performance in both the.
1494 852 902 261 1183 632 1559 312 73 1430 749 457 1524 631 185 1268 28 540 506 1221 19 724 1361 1116 709 167 216 1013 864 900 1378 1359 1163 217 140 321 1126 377 1352