This article aims to introduce the installation centos7 manual zoning issues, and soft and hard raid question corresponds. Centos7 in the new system, you need to manually partition, provide us with three options:
In the figure above, the default option is "Standard Partition", which means to create a standard partition, but also we want to select items. Others such as "RAID Partition" means that the RAID (redundant array of disks) partitions, RAID functions in the enterprise is generally more efficient bronze drum Oh physical hardware to complete the hardware RAID card, the poor performance of the operating system RAID function, redundancy it also limited by the operating system, so that enterprises rarely used, and means that the LVM logical volume manager, it set a good partition size dynamically adjusted, provided that all the partition format is required well in advance LVM format, partition labeled 8e, the business environment partitions are usually planned in advance on demand, there is very little subsequent adjustment of demand and performance LVM and standard partitions, and hardware RAID card, there is still a certain gap, therefore, if there is no special needs, do not select LVM and software RAID partitions. Secondly Create / boot partition, the size should be 200M, / boot as the boot partition, the system will not be as time increases.
Report: on the issue of soft and hard raid
Hard RAID: hardware is hard to achieve by RAID RAID functions, such as: a variety of RAID cards, as well as on-board RAID were able to do hard RAID.
Soft RAID: done by using operating system software RAID RAID functionality is, for example: in l under inux operating system, with three RAID5 hard to do.
Supplementary: RAID is also full of soft, semi-hard and semi-soft full hard points, all soft RAID refers to all the features of RAID are the operating system (OS) and the CPU to complete, no third-party control / processing (referred to as the industry RAID coprocessor --RAID co-processor) and I / O chips. Thus, the task of dealing with all of the RAID by the CPU to complete, you can imagine this is the lowest efficiencies of an RAID. Half - soft RAID is mainly lack their own I / O processing chip, so this work is still done by the CPU and the driver. Moreover, the half - soft RAID used in RAID control / processing chips abilities are weak, can not support higher RAID level. Full hard RAID is fully equipped with its own RAID control / processing and I / O processing chip, and even buffer array (Array Buffer), the CPU utilization and overall performance are the three types most advantage, but equipment costs are also the highest of the three types.
First, the performance
This is probably the most important aspect of using RAID is to improve performance. In theory, the use of single-use hard disk RAID0 can get double speed, with a soft / hard RAID0 can be close to this speed. Use a soft RAID CPU utilization rate is higher, so the performance, RAID hard to lead.
Second, stability
RAID is done in pursuit of performance, it is generally use 7.2k rpm or 10k, 15k rpm hard drive. The heat mainstream market 7.2k generally larger hard drive, and put the two in the chassis, cooling has been a problem, let alone three. After all, stability overrides everything, if the hard disk is burned more harm than good. Moreover, some case simply does not fit three hard drives. Therefore, the use of RAID hard stability is higher.
Mainstream server operating system, the new version of the basic support software RAID, but if the operating system is a problem, soft RAID hung up. Hardware RAID compatibility is much better, if the system is a problem, do system maintenance, data recovery is much more convenient.
Fourth, security
Software RAID security is not good, when there is a hard drive is damaged, it can not achieve reconstruction of function, but also in its limitations, but there is a hard RAID hard drive is lost, it can achieve reconstruction, and if RAID is damaged, it you can replace the RAID card, the function without data loss.