Data loss? So SMR -Technik – Wintotal.de helps

At the SMR, so that Shingled Magnetic Recordingit is a further development of the Perpendicular Magnetic Recordings (PMR). In this memory process, data is written on the magnetic slices of the hard drive. Unlike the PMR procedure In the case of SMR technology, the individual data traces described slightly overlapping And not separated from each other. This makes it possible to save more data on an area of ​​the same size. With this method, both the Data capacity as well as the data density increased. However, these advantages also face disadvantages, such as the loss of data.

The writing reading head is smaller than the writing unit dimensioned, which means that the readability of the data is still available despite the partial overwriting. Due to the overlapping description, however, it is necessary that the neighboring traces must also be re -described in the event of a writing process.

However, data recovery of hard drives with SMR technology is associated with increased effort due to the special technology. The following article shows why this is and what is characterized by SMR technology.

The areas of application from SMR

SMR technology is mainly used for data carriers that have a very high storage capacity. Recently turn the Manufacturer Seagate and Western Digital However, the method also applies to significantly smaller data carriers.

The reason is that the manufacturing costs are relatively low today, the same applies to material consumption. However, existed No special labeling for that, whether the hard drive uses SMR or PMRwhich is why problems with different storage methods can occur. Especially the users of external hard drives often do not know which method is used. But that shouldn't stay that way for long. Because in the United States there are already first complaints, including the manufacturer Western Digital, because it installed slower SMR hard drives in NAS servers without pointing out the consumer.

The advantages of SMR

The SMR technology offers some advantages. This includes, for example, that a round 25 percent higher storage capacity and a higher memory density is created. In addition, the cost of manufacturing is low. The method is particularly suitable for long sequential writing processes.

However, it falls Writing speed lower from because the neighboring traces must always be described again during the writing process. So if many random and short writing processes are mainly carried out, SMR is less suitable.

This is how the SMR technology works

As already described, the neighboring traces must also be described in the course of the writing process. So that this process does not lead to the full magnetic window, this is divided into different zones, each of which has a certain number of traces. In addition, there is one on the hard drive Cachein which the data that is rewritten are stored.

The hard drive can therefore be compared to a warehouse in which there are different large packages. These packages form the zones on the hard disk. In a large package, 20 smaller packages are housed that correspond to the overlapping traces. The data are then small items that are distributed in the respective parcels.

When packages, parcels and content are replaced …

If a certain object has to be exchanged from one of these packets, it must be removed from the large package using a machine that corresponds to the writing head on the hard drive and unpacked in another room, the cache.

In the first step, all small packets must then be removed from the large package until the desired package is found. After that, the desired item can be removed from the package. The parcels then have to be packed back into the large package and it can be brought back to the warehouse using the machine.

For this procedure, of course More RAMAs with the method, in which an object is immediately removed from the package on the shelf. That is why the writing speed is much lower.

Data rescue for SMR hard drives

With SMR technology, a division into different packages is made. These have to be unpacked, changed and then packed again if there is a change.

Because the packages are bundled – the traces overlap – the previously established is Standard procedure of data recovery hardly possible anymore. Therefore, more effective and innovative procedures must be developed and tried out. Compared to the data rescues in a PMR technology, the development and time expenditure is much higher.

In the case of newer drives, saving the data is also a greater challenge because there is no self -contained service area. Therefore, processing is not easily possible.

The solution: The only way to get to the data provides that Data Mining However. However, the structure of the folders is lost. This problem currently occurs in a suffering from the manufacturer Western Digital on, however, the other manufacturers will soon follow suit. The future goal is to find a solution for efficient restoration of the data together with the manufacturers, without being lost.

Das Data Mining

As part of the exemplary warehouse, the service area can be compared with a computer that contains all information about which space is stored. If access to this computer is blocked, the individual objects must be selected on their own without help.

This means that each individual package is unpacked, which has to be cleared out 20 parcels and have to be searched for in the respective object. This makes it quite possible to find all objects at some point, after which the packages and parcels are unsorted across the entire warehouse and there is a large chaos.

The SMR technology-a conclusion

Basically, the use of SMR technology offers a variety of advantages, especially with regard to the storage capacity. However, the method for restoring data is a great risk if there is a defect in the hard drive.

The data recovery is extremely difficult in the course of the standard procedures and can only be implemented by a very high development and time expenditure.

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