CN103475709B - A kind of copy dynamic control method towards cloud computing platform and system thereof - Google Patents

Abstract

The invention provides a kind of copy dynamic control method towards cloud computing platform and system, the method comprises the following steps: set copy minimum availability R_exp；Obtain minimum number of copies r in unit interval t_min；Judge whether system resource exists waste；Obtain the replica node cost sequence to standby copy node；Obtain the standby copy node for placing copy；By copy replication to standby copy node.The method and system thereof, for improving the reliabilty and availability of data in cloud computing, reach the balance between availability and cost-effectivenes.

Description

A kind of copy dynamic control method towards cloud computing platform and system thereof

Technical field

A kind of method that the present invention relates to Distributed Calculation and field of cloud calculation, a kind of pair towards cloud computing platform This dynamic control method and system thereof.

Background technology

Along with computer technology and the development of network technology, Internet scale constantly expands, and the network bandwidth improves constantly. The fast development of Internet, various information are enlisted the services of wherein, define a huge wide information space, magnanimity Data leave in this space.

Traditional centralised storage system leaves in data on a single equipment, and all access to data and request will By this equipment.This way causes the load of this equipment relatively big, becomes the bottleneck of system, it is impossible to meet Mass storage to can By property and the needs of safety.How to go to store these data, user can rapidly and efficiently be found and obtain required for oneself Resource, be one of the problem that have to solve of internet development.

In this context, cloud storage is suggested as a kind of brand-new solution.Cloud storage system passes through cluster application, grid Different types of storage devices a large amount of in network are gathered association by application software by the technology such as technology or distributed file system With work, common externally offer data storage and Operational Visit function.Not only increase the reliability of system, availability and access Efficiency, is also easy to extension.

In cloud storage system, data trnascription is the ingredient that it is important.How to create data trnascription, how to delete data trnascription, How to select data trnascription, how to manage the vital task that copy resource is the management of cloud storage system data trnascription.On suitable opportunity Create with suitable node or delete corresponding copy, it is possible to being effectively improved the access speed of data, reduce network bandwidth consumption and all Balance system loads, and can keep the availability that data are higher simultaneously.

Copy resource is moved by the replica management technology demand according to system the parameter index by monitoring system in cloud storage State planning, adjustment, be one of key element affecting cloud computing system performance.Current cloud storage is based particularly on HDFS framework Cloud storage system remains some shortcomings in this aspect.

First it is the problem of storage scheduling of resource shortage motility.Owing to the demand of different pieces of information is also not quite similar by user, such one Some data file can be made to become " focus ", and some data file is relative to unexpected winner.Therefore managed in cloud computing stored copies It is irrational in journey making no exception these data files, needs a kind of dynamic replication management strategy distinguishing different pieces of information demand.

Next to that the problem that Replica placement selects.Cloud storage system based on HDFS framework is to randomly choose when selecting Replica placement , so do not account for the communication cost that user accesses.

For the problems referred to above, a kind of Novel cloud stored copies management method of research and system thereof are significant.

Summary of the invention

For overcoming above-mentioned the deficiencies in the prior art, the present invention provide a kind of copy dynamic control method towards cloud computing platform and System, the method and system thereof are for improving the reliabilty and availability of data in cloud computing.

Realizing the solution that above-mentioned purpose used is:

A kind of copy dynamic control method towards cloud computing platform, it thes improvement is that: said method comprising the steps of:

I, setting copy minimum availability R_exp；

II, minimum number of copies r obtained in unit interval t_min；

III, judge whether system resource exists waste；

IV, the cost sequence of acquisition replica node to standby copy node；

V, acquisition are for placing the standby copy node of copy；

VI, by copy replication to standby copy node.

Further, described step I includes following:

S101, according to design require and systematic function, determine acquiescence number of copies m of current file f；

S102, acquisition replica node set F_A={A₁, A₂..., A_m}；

S103, using replica node adjacent node as standby copy node set F_B={B₁, B₂..., B_n, set copy minimum and can use Rate R_exp。

Further, described step II includes following:

The read request number RN of copy in S201, record unit time t_i(0 ＜ i ＜ m), effective read request number ERN_i(0<i<m)、 Write request number WN_i(0 < i < m) and effective write request number EWN_i(0<i<m)；

S202, obtain the average availability of current copy according to the read-write number of times in unit interval t and effectively read-write number of times $\frac{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{ERN}}_i+{\mathrm{EWN}}_i)}{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{RN}}_i+{\mathrm{WN}}_i)};$

S203, according to described copy minimum availability R_expObtain minimum number of copies r_min, such as following formula (1):

$1-{(1-\frac{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{ERN}}_i+{\mathrm{EWN}}_i)}{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{RN}}_i+{\mathrm{WN}}_i)})}^{r_{\min }}\&GreaterEqual;R_{\exp }---\left(1\right);$

Wherein, RN_i(0 < i < m) is the read request number of copy, ERN_i(0 < i < m) is effective read request number of copy, WN_i(0 < i ＜ m) is the write request number of copy, EWN_i(0 < i < m) is effective write request number of copy, and m is current copy Number, R_expFor copy minimum availability.

Further, described step III includes following:

S301, according to minimum number of copies r_minJudging whether system resource exists waste with current copy number m, waste then enters S302, Balance then enters S303, and number of copies is crossed and entered S304 at least；

S302, work as r_min< during m, there is waste in system resource, as following formula (2) is worked as according to effective read-write requests acquisition in time t Average service rate PN of front copy_i, by described average service rate PN_iMinimum copy is labeled as hidden file, in the time $\max ({\mathrm{ERN}}_i,{\mathrm{EWN}}_i)\&times;(e^{-|{\mathrm{ERN}}_i-{\mathrm{EWN}}_i|}+1)\&times;t$ Do not activate in if, delete completely；

${\mathrm{PN}}_i=\frac{{\mathrm{ERN}}_i+{\mathrm{EWN}}_i}{t}(0<i<m)---\left(2\right)$

Wherein, ERN_i(0 < i < m) is effective read request number of copy, EWN_i(0 < i < m) is effective write request number of copy；

S303, work as r_minDuring=m, maintain copy constant；

S304, work as r_min> m time, the average availability of copy less than set minimum availability R_exp, check in system and whether contain The hidden file of current copy；If existing, then activating hidden file, if not existing, performing step IV.

Further, described step IV includes following:

S401, obtain two internodal call duration times and network hop count by IP address；

S402, obtain replica node X according to call duration time and network hop count to the renewal cost between standby copy node Y C_{X, Y}, the reading cost of user node u to standby copy node Y is C_{U, Y}, it is thus achieved that update cost, read cost all such as following formula (3):

C_{X, Y}=RT_{X, Y}/α+HC_{X, Y}(0<α<1) (3)

Wherein, RT_{X, Y}For from nodes X to Y, then the two-way time from Y to X；α is factor of influence, sets according to network condition Fixed, span is 0-1；HC_{X, Y}Network hop count for X to Y；

S403, acquisition replica node A₁To standby copy node B₁Total cost A of communication produced₁B₁；

A₁B₁=C_{A1, B1}+C_{U, B1} (4)

Wherein, C_{A1, B1}For replica node A₁To standby copy node B₁Between renewal cost, C_{U, B1}For user node u to standby pair This node B₁Reading cost；

S404, acquisition replica node A₁To standby copy node B_jTotal cost A of (0 ＜ j ＜ n)₁B_jThe cost sequence of composition F₁={ A₁B₁, A₁B₂..., A₁B_n}；

S405, acquisition replica node A_i(0 ＜ i ＜ m) arrives standby copy node B_jThe cost sequence of (0 ＜ j ＜ n) F_i={ A_iB₁, A_iB₂..., A_iB_n(0 ＜ i ＜ m).

Further, described step VI includes following:

S501, to each described cost sequence F_iCarry out sort ascending, it is thus achieved that cost sequence { A_iB₁', A_iB₂' ..., A_iB_n', reject Described cost sequence { A_iB₁', A_iB₂' ..., A_iB_n' after (n+m-r_min) individual element obtains new cost sequence ${F_i}^{\&prime;}=\{A_i{B_1}^{\&prime;},A_i{B_2}^{\&prime;},...,A_i{B_{m-r_{\min }}}^{\&prime;}\}(0<i<m);$

S502, described new cost sequence merger is obtained set MF=F₁′∪F₂′∪...∪F_m', carry out being incremented by row to set MF Sequence, obtains cost sequence G={A_iB_j|A_iB_j∈ MF, 1≤i≤m, 1≤j≤n}；

S503, remove k element after described cost sequence G, k=(m-1) (r_min-m), it is thus achieved that for placing the standby of copy With the cost sequence MF '={ A of replica node_iB_j′|A_iB_j' ∈ MF, 1≤i≤m, 1≤j≤n}.

A kind of novel cloud storage system applying to the above-mentioned copy dynamic control method towards cloud computing platform, its improvements exist In: described system includes monitoring system and the data-storage system connected by user agent module.

Further, described monitoring system includes Replica placement module, copy monitoring system and copy removing module；Described copy Monitoring system sends information to described Replica placement module and copy removing module, described Replica placement module and copy respectively and deletes Module sends information to described user agent module respectively；Described user agent module sends information to described copy monitoring system.

Further, described data monitoring system includes replica node and the standby copy node corresponding with described replica node；Institute State user agent module respectively with the node communication of described data monitoring system.

Compared with prior art, the method have the advantages that

(1) method of the present invention is when network peak period or mechanical disorder, can increase copy dynamically, prevent user from occurring The situation that cannot access or wait, when visit capacity reduces, can dynamically delete the copy that utilization rate is relatively low, save resource Unnecessary consumption, remain to keep higher availability simultaneously.

(2) method of the present invention is when Replica placement, it is contemplated that is positioned over and reads cost and update the node that cost is relatively low, from whole Reduce the communication cost of network on body, preferably improve copy availability；No matter the dynamic replication model that the present invention proposes exists In memory space utilization rate or compared to traditional fixing Replica placement, there is sizable advantage in communication cost.

(3) the approach application dynamic storage model of the present invention, is monitored the availability of copy in real time, calculates current optimal Copy amount, when best copy is in right amount more than current copy number, then can use copy replication strategy, if best copy is appropriate During more than current copy number, then can use copy deletion strategy, reaction is timely and flexible, has ensured that access resource and data can be used Property.

(4) the approach application dynamic storage model of the present invention, largely reduces the requirement of the network bandwidth, and keeps relatively High availability；What is more important, the method for the present invention, in the case of replica node breaks down simultaneously, remains to quickly Realize the recovery of data, ensure the availability of data.

(5) method of the present invention considers focus situation and the problem of Replica placement selection, the replica management model of proposition of data Deletion copy can be increased dynamically, greatly reduce the demand of the network bandwidth, save Internet resources, ensure availability of data, System is run more efficient safer.

Accompanying drawing explanation

Fig. 1 is the system construction drawing dynamically controlled towards the copy of cloud computing platform；

Fig. 2 is the dynamic control flow chart of copy towards cloud computing platform.

Detailed description of the invention

Below in conjunction with the accompanying drawings the detailed description of the invention of the present invention is described in further detail.

As it is shown in figure 1, Fig. 1 is the system construction drawing dynamically controlled towards the copy of cloud computing platform；A kind of facing cloud calculates flat The system that the copy of platform dynamically controls includes user agent module, monitoring system and data-storage system.

Monitoring system includes Replica placement module, copy monitoring system and copy removing module；Copy monitoring system sends letter respectively Breath to Replica placement module and copy removing module, Replica placement module and copy removing module sends information to user agent respectively Module；User agent module sends information to copy monitoring system.

Data monitoring system includes replica node and standby copy node (replica node 1 and the standby copy corresponding with replica node Node 1, replica node 2 and standby copy node 2 ... replica node N and standby copy node N)；User agent module is divided Not and the node communication of data monitoring system.

As in figure 2 it is shown, Fig. 2 is the dynamic control flow chart of copy towards cloud computing platform；A kind of pair towards cloud computing platform This method dynamically controlled, can effectively improve the availability of copy, reduce unnecessary resource consumption simultaneously when disposing. The availability to each copy that the copy monitoring system of this system is real-time is monitored, such that it is able to calculate current best copy Number, deletes the copy that utilization rate is minimum when copy is too much, when copy is less than best copy number, dynamically increases copy, And it is positioned over rational position.So can either keep higher availability, reduce unnecessary resource consumption simultaneously, save Cost.The method comprises the following steps:

Step one, setting copy minimum availability R_exp。

Requiring and systematic function according to design, determining the acquiescence replica node number m of current file f, replica node collection is combined into F_A={ A₁, A₂..., A_m, it is F using each copy adjacent node as standby copy node set_B={ B₁, B₂..., B_n}。

Set copy minimum availability R_exp, minimum availability needs copy availability to set according to system, such as 95%, 98% etc..

Step 2, read request number RN according to copy_i(0 ＜ i ＜ m), effective read request number ERN_i(0 ＜ i ＜ m), write request number WN_i(0 ＜ i ＜ m) and effective write request number EWN_i(0 ＜ i ＜ m) obtains minimum number of copies r in unit interval t_min。

Obtain current copy in real time and can use number m, the read request number RN of each copy in record unit time t_i(0 ＜ i ＜ m), effectively reads Number of request ERN_i(0 ＜ i ＜ m), write request number WN_i(0 ＜ i ＜ m), effective write request number EWN_i(0 ＜ i ＜ m).

The average availability of current copy is tried to achieve according to the read-write number of times in unit interval t and effectively read-write number of timesUtilize copy minimum availability R_expDetermine minimum number of copies r_min, determine minimum number of copies r_min Such as following formula (1):

$1-{(1-\frac{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{ERN}}_i+{\mathrm{EWN}}_i)}{\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}({\mathrm{RN}}_i+{\mathrm{WN}}_i)})}^{r_{\min }}\&GreaterEqual;R_{\exp }---\left(1\right)$

Wherein, RN_i(0 < i < m) is the read request number of copy, ERN_i(0 < i < m) is effective read request number, WN_i(0 < i < m) is write request number, EWN_i(0 < i < m) is effective write request number, and m is current copy number, R_expFor copy Minimum availability.

Step 3, according to best copy number r_minJudge whether system resource exists waste with current copy number m.

Work as r_min< during m, representing that current copy number is too much, there is waste in system resource, performs step 4 and deletes copy；

Work as r_minDuring=m, represent that system resources consumption and copy availability reach balance, maintain copy constant；

Work as r_min> m time, represent current copy number very few, the average availability of copy less than set minimum availability R_exp, perform Step 5 increases copy.

Step 4, deletion copy.

Average service rate PN of current copy is tried to achieve according to the effective read-write requests number in unit interval t_i, such as following formula (2), incite somebody to action Utilization rate PN_iMinimum copy is labeled as hidden file.

${\mathrm{PN}}_i=\frac{{\mathrm{ERN}}_i+{\mathrm{EWN}}_i}{t}(0<i<m)---\left(\text{2}\right)$

Wherein, RN_i(0 < i < m) is the read request number of copy, ERN_i(0 < i < m) is effective read request number, EWN_i(0 < i < m) is effective write request number, and m is that current copy can use number, and t is the unit time.

Delete copy according to copy hot topic degree, i.e. set the time to be deleted according to the copy effectively read-write number of times in time t, In the timeDo not activate in if, delete completely,Representing the difference according to read-write number of times, the time to be deleted is the most different, if Copy is to read to write few more, then erasing time tends to reading number of times and is multiplied by time t, i.e. ERN_i× t, if copy is to write many readings less, Then erasing time tends to EWN_i× t, if read-write is equal mutually, then erasing time tends to (EWN_i+ERN_i)×t。

Step 5, increase copy.

Check the hidden file whether containing current copy in system.If existing, then activate hidden file.If not existing, perform Subsequent step.

Step 6, obtain internodal call duration time and network hop count according to IP address, thus obtain the renewal cost of node.

Obtain two internodal call duration times and network hop count by IP address, and then calculate pair according to formula (3) This node A_iTo standby copy node B_jBetween renewal costUser node u to standby copy node B_jReading cost ForObtain and update cost, reading cost all such as following formula (3):

C_{X, Y}=RT_{X, Y}/α+HC_{X, Y}(0<α<1) (3)

Wherein, RT_{X, Y}For from nodes X to Y, then the two-way time from Y to X, α is that factor of influence is (according to network condition Setting factor of influence, span is 0-1), HC_{X, Y}Network hop count for X to Y.

Step 7, acquisition replica node A_i(0 < i < m) arrives standby copy node B_jThe cost sequence of (0 < j < n).

Standby copy node B_jTotal cost A of communication that (0 < j < n) produces_iB_jIncluding replica node A_iTo standby copy node B_jBetween Renewal costWith user node u to standby copy node B_jReading costAs following formula (4) always obtains communication Cost A_iB_j；

$A_i{B}_j=C_{A_i,B_J}+C_{u,B_j}---\left(4\right);$

Wherein, A_iB_jFor by node A₁Start to standby copy node B_jTotal cost of (0 < j < n),For replica node A_iArrive Standby copy node B_jBetween renewal cost,For user node u to standby copy node B_jReading cost.

The total cost of communication according to each standby copy node, it is thus achieved that by node A₁Start to standby copy node B_j(0 < j < n) total Cost A₁B_jCost sequence F of composition₁={A₁B₁, A₁B₂..., A₁B_n}；Thus obtain replica node A_i(0 < i < m) arrives standby copy Node B_jThe cost formula of (0 < j < n), i.e. cost sequence F_i={A_iB₁, A_iB₂..., A_iB_n}(0<i<m)。

Step 8, to cost sequence F_i={A_iB₁, A_iB₂..., A_iB_n(0 < i < m) tentatively delete choosing.First, to cost sequence F_iSort ascending obtains new cost sequence { A_iB₁′,A_iB₂′,...,A_iB_n′}；Secondly as current copy number is m, minimum needs Seeking number is r_min, then also need to select r_min-m copy, and a combination has n element, therefore need after rejecting n-(r_min-m) individual element, it is thus achieved that the r of Least-cost_minThe new cost sequence of-m element ${F_i}^{\&prime;}=\{A_i{B_1}^{\&prime;},A_i{B_2}^{\&prime;},...,A_i{B_{{m-r}_{\min }}}^{\&prime;}\}(0<i<m).$

M the new cost sequence obtained after tentatively deleting choosing is integrated in a set, i.e. MF=F₁′∪F₂′∪...∪F_m', Set MF is carried out sort ascending, obtains sequence cost { A_iB_j| A_iB_j∈ MF, 1≤i≤m, 1≤j≤n}.

Make G={A_iB_j| A_iB_j∈ MF, 1≤i≤m, 1≤j≤n}, rejects k element below, wherein, k=(m-1) (r_min-m), Thus obtain r_min-m standby copy node is used for placing copy f, obtains new sequence cost MF '=(A_iB_j′|A_iB_j' ∈ MF, 1≤i≤m, 1≤j≤n}, copies to copy f in the node element in MF ' set.

Finally should be noted that: above example is merely to illustrate the technical scheme of the application rather than the restriction to its protection domain, Although being described in detail the application with reference to above-described embodiment, those of ordinary skill in the field are it is understood that this area Technical staff still can carry out all changes, amendment or equivalent to the detailed description of the invention of application after reading the application, but These changes, amendment or equivalent, all within the claims that application is awaited the reply.

Claims (7)

1. the copy dynamic control method towards cloud computing platform, it is characterised in that: said method comprising the steps of:

I, setting copy minimum availability R_exp；

II, minimum number of copies r obtained in unit interval t_min；

III, judge whether system resource exists waste；

IV, the cost sequence of acquisition replica node to standby copy node；

V, acquisition are for placing the standby copy node of copy；

VI, by copy replication to standby copy node；

Described step I includes following:

S101, according to design require and systematic function, determine acquiescence number of copies m of current file f；

S102, acquisition replica node set F_A={ A₁,A₂,...,A_m}；

S103, using replica node adjacent node as standby copy node set F_B={ B₁,B₂,...,B_n, set copy minimum availability R_exp；

Described step II includes following:

The read request number RN of copy in S201, record unit time t_i(0 ＜ i ＜ m), effective read request number ERN_i(0 ＜ i ＜ m), write request number WN_i(0 ＜ i ＜ m) and effective write request number EWN_i(0 ＜ i ＜ m)；

S202, obtain the average availability of current copy according to the read-write number of times in unit interval t and effectively read-write number of times

S203, according to described copy minimum availability R_expObtain minimum number of copies r_min, such as following formula (1):

Wherein, RN_i(0 ＜ i ＜ m) is the read request number of copy, ERN_i(0 ＜ i ＜ m) is effective read request number of copy, WN_i(0 ＜ i ＜ m) is the write request number of copy, EWN_i(0 ＜ i ＜ m) is effective write request number of copy, and m is current copy number, R_expFor copy minimum availability.

A kind of copy dynamic control method towards cloud computing platform, it is characterised in that: described step III includes following:

S301, according to minimum number of copies r_minJudging whether system resource exists waste with current copy number m, waste then enters S302, and balance then enters S303, and number of copies is crossed and entered S304 at least；

S302, work as r_minDuring ＜ m, there is waste in system resource, if following formula (2) is according to average service rate PN of effective read-write requests acquisition current copy in time t_i, by described average service rate PN_iMinimum copy is labeled as hidden file, in the timeDo not activate in if, delete completely；

Wherein, ERN_i(0 ＜ i ＜ m) is effective read request number of copy, EWN_i(0 ＜ i ＜ m) is effective write request number of copy；

S303, work as r_minDuring=m, maintain copy constant；

S304, work as r_minDuring ＞ m, the average availability of copy is less than minimum availability R set_exp, check the hidden file whether containing current copy in system；If existing, then activating hidden file, if not existing, performing step IV.

A kind of copy dynamic control method towards cloud computing platform, it is characterised in that: described step IV includes following:

S401, obtain two internodal call duration times and network hop count by IP address；

S402, obtain replica node X according to call duration time and network hop count to renewal cost C between standby copy node Y_X,Y, the reading cost of user node u to standby copy node Y is C_u,Y, it is thus achieved that update cost, read cost all such as following formula (3):

C_X,Y=RT_X,Y/α+HC_X,Y(0 ＜ α ＜ 1) (3)

Wherein, RT_X,YFor from nodes X to Y, then the two-way time from Y to X；α is factor of influence, sets according to network condition, and span is 0-1；HC_X,YNetwork hop count for X to Y；

S403, acquisition replica node A₁To standby copy node B₁Total cost A of communication produced₁B₁；

A₁B₁=C_A1,B1+C_u,B1 (4)

Wherein, C_A1,B1For replica node A₁To standby copy node B₁Between renewal cost, C_u,B1For user node u to standby copy node B₁Reading cost；

S404, acquisition replica node A₁To standby copy node B_jTotal cost A of (0 ＜ j ＜ n)₁B_jCost sequence F of composition₁={ A₁B₁,A₁B₂,...,A₁B_n}；

S405, acquisition replica node A_i(0 ＜ i ＜ m) arrives standby copy node B_jCost sequence F of (0 ＜ j ＜ n)_i={ A_iB₁,A_iB₂,...,A_iB_n(0 ＜ i ＜ m).

A kind of copy dynamic control method towards cloud computing platform, it is characterised in that: described step VI includes following:

S501, to each described cost sequence F_iCarry out sort ascending, it is thus achieved that cost sequence { A_iB₁′,A_iB₂′,...,A_iB_n', reject described cost sequence { A_iB₁′,A_iB₂′,...,A_iB_n' after (n+m-r_min) individual element obtains new cost sequence

S502, described new cost sequence merger is obtained set MF=F₁′∪F₂′∪...∪F_m', set MF is carried out sort ascending, obtains cost sequence G={A_iB_j|A_iB_j∈MF,1≤i≤m,1≤j≤n}；

S503, remove k element after described cost sequence G, k=(m-1) (r_min-m), it is thus achieved that for placing the cost sequence MF '={ A of the standby copy node of copy_iB_j′|A_iB_j′∈MF,1≤i≤m,1≤j≤n}。

5. the novel cloud storage system of the copy dynamic control method towards cloud computing platform applying to above-mentioned any claim 1-4, it is characterised in that: described system includes monitoring system and the data-storage system connected by user agent module.

Novel cloud storage system the most as claimed in claim 5, it is characterised in that: described monitoring system includes Replica placement module, copy monitoring system and copy removing module；Described copy monitoring system sends information to described Replica placement module and copy removing module respectively, and described Replica placement module and copy removing module send information to described user agent module respectively；Described user agent module sends information to described copy monitoring system.

Novel cloud storage system the most as claimed in claim 5, it is characterised in that: described data-storage system includes replica node and the standby copy node corresponding with described replica node；Described user agent module respectively with the node communication of described data-storage system.