The data safety can is divided in to deliver the safety substantially and saving safety.Deliver the safety points in data of bornly, deliver and visit process, insuring the integrity, accuracy of the data and lining up his sex.Black guest, fire wall...etc., all belong to the concept of deliver the safety.The saving safety points to keep in the data up insure the integrity, credibility and adjust to use effectively, usually include two layer meanings:While is the credibility of the saving equipments oneself and can use sex( equipments safety), two is a logic safety that keeps on the saving equipments the data.( application safety)This text emphasizes to analyze the realization saving safety of essential main factor and familiar mistake area, in order to provide to constructive the guidebook for the business enterprise and organization.

RAID- obtain main tool of the equipments safety

In 1988, at in order to raise the disk, the whole calculator industry was a bitter bitterness flounder of the function and credibilities of the big capacity disk particularly, the Patterson of the American bao gram benefit university of California waited for someone to announce 《 the A Case for Redundant Arrays of Inexpensive Disks( RAID) 》 , point out with the revolution way of thinking, the redundancy array that makes use of many independently small disk to constitute set up the big disk of logic, can make a convenience of the ground to carry out the high performance and high and dependables, the profession of RAID rose from now on.

Really, although more than 20 years the disk technique flies to develop soon, the single dish capacity and access speeds all had the substantial exaltation, the equipments safety that saves the system still is to take RAID as the sill.The equipments safety that technique of RAID bring has two layer meanings:
High credibility- When the equipments break down, can complete the saving work of data still while lose stripe the appearance;
High can use- When the equipments break down, the system can make a convenience of the instauration to permit the wrong ability, coming out the degradation appearance.
The applied development of RAID experienced the pure software, inside place the plank card and independences to establish three stages outside.Pure software and inside place the plank card RAID cost lower, but take up the host resources, the function is subjected to the limit and difficult in excellent turn, particularly is to did not solve the er with the application system, be When the host environment damage, if can't guarantee that the complete instauration install, may can't cause data within the dish recover.Therefore, win the upscale system of RAID to all have already adopted the form that independence outside establish currently.

RAID- to apply the safety incapable is dint

The host operate system and it last the data that the application procedure produce when circulate, generally was be called on-line data.Keep the saving system of the on-line data because of was also be called on-line saving.The near line that near two in the last years industry heats fry is saving, belonging to the on-line saving category essentially, just lying on-line data in the pin a lower data of interview deposit second class in the quality, to economize the investment cost.

Is an applied vivid of guarantee to the on-line saving core request, concrete body now for fraction according to measure multifarious, random and read and write abreast.This aspect requests to save to lie the quality to have the special features- SCSI disk and disk of FCs of corresponds to emerge with the tide of the times, on the other hand then requesting data can drive operate system direct interview, keep for the document format of the particular operate system in order to look for the address quickly.

The operate system is an on-line applied core.One of the calculator system safety standard of the authority, the orange skin book( the Trusted Computer System Evaluation Criteria, then be subjected to trust the calculator system to evaluate the basis) of the safe center promulgation of American national calculator point out, operate system of easy use sex and safeties and can't look after both sides, the company of the extensive usage uses the operate system, such as the Windows, each kind of Unix, Linux etc., all belonging to the C1 or the Class of C2 of medium etc. safety.

So the operate system says for the data that is insecure, because of in these in general use terraces, customer or applied procedure can very easily logarithms according to carry on any operation with document, include to increase, delete, modify etc..The artificial in the mood for or not intentional mistake operation, the breakage of the virus, application the Bug of the software, the procedure circulates the conflict etc., all may cause on-line data throw lose.

Therefore, the on-line system guarantee applies the price of vivid is a sacrifice application safety.A" good" the host can protect ten thousand viewpoints of the matter great luck are a the liao that kind is terrible to grow to spread.

The data backup- the application only one guarantee of the safety

Up to the present, guarantee the only one way of the application safety is a data backup.

The purpose of the data backup is the history that the periodic keeps the on-line data, for the purpose of the on-line data occurrence damage, the usage backup Data Recovery arrives the mistake to take place the previous appearance, to insure normal interview of the data.

Backup with saving safe leader principal item of the guarantee data of, insure through a series of means of strict backup strategy, process...etc. the data application can't to the backup data of safe creation influence.

After"9 ·s 11" affairs, the big turbulence of the financial market of world provided the warning of a he person.According to the United States Texas the university investigates the manifestation, the IT application develops the level of the United States of today, the disaster data throws to lose and would make 94% company close down within two years.

Speak from the concept, the backup purchases the insurance for the data.The applied level of IT is more high, data become the Life Line of the organization more, so at enter today of knowledge-based economy, the heart saves on the backup by luck, just like in used for the business enterprise corpus property high risk wager bao .

The differentiation of the backup and backup

Positive is divided into on-line data ratings is on-line similar to near line data, off-line data may also such as the life cycle theories backup and the backup data, since low investment and luck wei cost.

The purpose of the backup is to check need the long-term fully or transfer the foreign land to keep/ the restored data deposits and can move to save to lie the quality up.Speak on the strict meaning, the purpose of the backup is not for the sake of the guarantee data safety, but just for carrying out the data warehouse.If say the dictionary of a head of backup, work the hour will usually turn over to use, the backup then seems daily pursuit in some borns keep the worth writing data over a long period of time, is transfer the bookcase ascend or check fully in the file building.

Therefore, although the backup data quantity after long-playing total amount the total amount can be very big, in saving system of good design of a backup period inside, the backup quantity is general only have one of several cents that backup quantity is even several very it a.

Magnetic tape backup

Close till 2002, the global backup market is always with the magnetic tape equip for main force.

The magnetic tape backup has the outstanding applied safety, because the data is on the magnetic tape of write the format as form of Byte- to- Byte, any host and applied softwares are all impossible to cross the backup the management software interview magnetic tape, so on-line carry any circumstance of the occurrence, all will not affect applied safety of the backup data.The equipments safety pole of the regrettable magnetic tape backup may worry: The credibility is low- the magnetic tape database is closed the easy machinery of suen to constitute not by the magnetic tape actuator, machine hand, magnetic tape...etc., the any little bit single breakdown all will cause backup have a miscarriage;
Can use sex bad- the magnetic tape did not permit the wrong ability, participating the magnetic tape set of the backup in any one some cassette tape of the dish, wear away, the mildewed orders the etc., all may can't cause whole backup recover.
Although some high levels factory house such as the Ultera Systems etc. provides the equal to disk RAID of the magnetic tape RAIT( the Redundant Array of Independent Tapes) product, the price is high, to common customer only the ability is plain and white snow.

Backup of D2D

Enter 21 centuries, the unit capacity price of the disk of ATA starts approach the traditional magnetic tape, gradual rise of the disk backup. The high equipments safety that makes use of the disk RAID solves the magnetic tape to equip related to slice the pain of the skin, causing the more and more big concern of industry.

Most in order to keep the disk backup of view and is a D2D( the disk arrives the disk), among them, the more mature is generally according to the disk snap shot technique.However the mirror be like type snap shot consumes the capacity to lead greatly, point the needle type snap shot although the support is similar the traditional backup increases to measure the snap shot, total owned the cost high, the main reason lies in the in general use backup software of nonsupport, must bind the expensive appropriation system.

See from the technique angle, the D2D also exists some core weaknesses, particularly is to depend on the document operate system, the data safety problem did not resolve still, a great deal of document system load, even make the data baud rate consumedly low in the ability that hardware have, cause the investment wasted.

Total to say, the backup of D2D is higher than the traditional backup method price and have to have another, but did not resolve the data safety problem.The EMC also released formally the virtual magnetic tape database product in the first half of 2004, symbolizing the disk backup of another one direction- the virtual magnetic tape database( VTL) is becoming the main current of the backup.

Virtual magnetic tape database of software

Positive be carry out by the software such as the earliest RAID similar, most in brief virtual magnetic tape database also is to be carry out by the software of, its method adds the virtual magnetic tape database( VTL) software control mold piece directly on the backup server, making the backup disk been a magnetic tape form now in the logical body to the server.

This project next, the backup disk is expose in the host operate system, so essentially and still on-line, although had the equipments safety that RAID provide, still can't the applied safety of the assurance data, so it can is used to only the normal regulations magnetic tape database saves the enclosure slowly.

For downplaying applied safety problem, parts of factory and gather the company install the software VTL mold piece in in the appropriation VTL server, with the sacrifice cost and proper go together with sex of price exchange the applied safety of the certain degree guarantee and functions to promote.

Virtual magnetic tape database of Block- Level

In 2002, the similar to technical contriver Quantum of magnetic tape of DLT, almost establish( Mirage and series of DX) outside released the virtual magnetic tape database of pure hardware at the same time, laid aside the dependence of the normal regulations disk application to the document system thoroughly, real realization with write with magnetic tape method of Byte- to- Byte of an Ultera of American professional saving factory Systems wrote the data toward disk.

Be like the end alignment independence of the disk RAID establishes outside, the virtual magnetic tape database( the Block- Level VTL) of the data piece class also completes to solve the er with the host system thoroughly, at the time of reserving the equipments safety that the disk RAID bring, having with the same applied safety of magnetic tape, the fish and bear's paws have both, making virtual opposite and other backup equipmentses of magnetic tape database of the data piece class have the obvious advantage:

Significant exaltation of function- can support the backup of near to the disk array extreme limit/ the instauration speed;
The immunity virus- application safety etc. is together the physics magnetic tape database;
Do away with the disk fragment- the guarantee function keeps on sex and disk efficiencies;
Did not turn to translate the data to deliver- good logarithms according to the acceptance dint that structure damage;
In general use in soft hardware environment of host- the absolution is proper to go together with, maintenance and management risk.
It is the main obstacle of 2003 check and supervision Block- level VTL expansion that price is higher to be prove, this mainly is because pure the hardware equipments cost is hard to lower quickly.

Enter 2004, the traditional magnetic tape database factory house, if the ADIC releases the Pathlight VX to wait the virtual magnetic tape database.At the same time along with sell the quantity to increase, the Block- level VTL starts descend, particularly eye-catcher is, the Ultera declare to release to enter door the virtual magnetic tape database of the class Mirage recently, the Chinese customer will be able to not buy the 2 TB capacity to 100,000 dollars prices, the pure hardware of the function equal to four high levels magnetic tape actuator suitable for use, do not need to support the virtual magnetic tape database.

Can foresee, the technique of Block- level VTL is like the technique of RAID of the end of 80's in 20 centuries to solve the on-line saving hard nut to crack so, a date that solves the backup hard nut to crack is already not far.

Conclusion

The disk RAID brought the equipments safety, but because of operate system of easy use sex and safeties and can't look after both sides, the applied safety of the data does not get any guarantee because of the RAID.The backup therefore becomes only one means that guarantees the data application safety.

Although the traditional magnetic tape backup has the good applied safety, the equipments safety perplexs the customer over a long period of time.Statistics according to the American Strategic Research Corporation, the American market of 2003 has already exceeded the magnetic tape according to the total amount of the disk backup, the American Taneja Group predicts more in April of 2004, future in 18 months,85% will be changed direction the disk backup by the magnetic tape backup to 100% business enterpriseses.

Virtual magnetic tape database of Block- level and have the applied safety of the traditional magnetic tape and the equipments safety of the disk RAIDs, will become essential equipments of the backup.