Can the hard drives in raid be interchangeable slots?

Problem

In the case of power outages, the configuration of the already configured raid in the hard disk disk position swap, the power-on will not affect the integrity of the original storage data, will cause data disaster?

Answer

This depends on the RAID controller's firmware design, and one of the most important is, where is the raid information (RAID metadata) recorded? You can record RAID information only on the storage unit and on the hard disk on the RAID controller.

If the raid information is recorded only on the controller, the data will be affected when the hard disk bits in the configured raid are swapped. This recording method is less used and only some low-end controllers are used at present.

It is also rare that raid information is recorded on the hard disk, and if the raid information is recorded on the hard disk only, the controller does not have the ability to record the raid configuration, is completely dependent on the hard disk, and has less security. If this is the case, replacing the raid disk bit does not cause a data disaster.

At present, most controllers are implemented to record the raid information on both the controller and the hard drive, so that if there is a failure in both, it can be restored through another copy. At the same time, the correctness of the raid information can be verified, the raid information stored on the controller as the main information, when the information in the raid and hard drive information is not the same, the need to manually judge processing (such as forced online). This kind of situation after replacing the hard disk bit, or automatically adjust, do not affect the data, or need to manually confirm. As long as the right operation, there will be no data disaster.

It must be noted, however, that the replacement of the raid disk bit is still quite dangerous, the more secure the RAID controller the more sensitive, the replacement of the bit caused by a little bit of interface loosening may cause the hard drive off the disk, thus affecting the entire RAID volume. Replacing the RAID disk bit operation only applies to migrating to another server or to the control of the disk array, but before migrating, try to back up the data as much as possible in case of an accident.

Source: http://zhangyu.blog.51cto.com/197148/133820