CN104461940A

CN104461940A - Efficient caching and delayed writing method for network virtual disk client side

Info

Publication number: CN104461940A
Application number: CN201410788824.XA
Authority: CN
Inventors: 苗阳
Original assignee: Nanjing LES Information Technology Co. Ltd
Current assignee: Nanjing LES Information Technology Co. Ltd
Priority date: 2014-12-17
Filing date: 2014-12-17
Publication date: 2015-03-25

Abstract

The invention discloses an efficient caching and delayed writing method for a network virtual disk client side. The efficient caching and delayed writing method has the advantages that multiple sectors are read for a reading request, partial transmission data quantity is increased slightly while transmission frequency is reduced effectively, and negative factors of network delay are avoided; for a writing request, to-be-written sector data are written into a local cache before returning, and the data are not really sent to a server side to generate a delay combination effect, so that the negative factors of network delay are avoided, and a network virtual disk with good performance, high stability and high adaptability can be achieved.

Description

Network virtual magnetic disk client high-efficiency buffer memory and delay wiring method

Technical field

The present invention relates to field of data storage, especially a kind of method to network virtual magnetic disk read-write on client side.

Background technology

The essence of network virtual magnetic disk system is exactly utilize disk drive technology, in an operating system the disk of virtual " truly ", all read-write requests of interception disk, is redirected to background server and stores, realize the virtual of storage by network remote.What virtual disk driver was simulated in client operating system is block device, all request of access all like for the same sector read-write requests of physical disk in fact, see at this level, only have reading and writing two kinds operation, sector number and the sector number of just each request are different.Noticing that operating system is to the read-write of disk, is always least unit with sector.

In the realization of network virtual magnetic disk system, what be difficult to most to overcome is efficiency, we know, the read or write speed of general USB flash disk is at 5 ~ 15MB/S, the read or write speed of PC hard disk is generally at 50 ~ 100MB/S, server S CSI disk can reach 300 ~ 500MB/S, network virtual magnetic disk is because need to be accessed by network remote, the efficiency of network has just become with postponing the maximum bottleneck restricting whole system, such as, under 100000000 net environment, the theoretical upper values of Internet Transmission is 12.5MB/S, in actual use, the highest general 8-10MB/S or lower of can only reaching, under such network condition, the efficiency of network virtual magnetic disk will be very low, more many all slowly than common U disk, substantially unavailable.

Summary of the invention

The object of the invention is the deficiency existed for prior art, a kind of network virtual magnetic disk client high-efficiency buffer memory is provided and postpones wiring method, for network bandwidth deficiency or unstable network, can realize that there is good performance, stability and adaptive network virtual magnetic disk.

For achieving the above object, network virtual magnetic disk client high-efficiency buffer memory of the present invention and delay wiring method can adopt following technical scheme:

A kind of network virtual magnetic disk client high-efficiency buffer memory and delay wiring method, comprising:

For read request, when needs read certain disk sector, some sectors that always order pre-read is follow-up backward, and by the data in the disk sector of all readings all stored in local cache, when again reading sector, search in present local cache, if having found, just directly return, no longer pass through Internet Transmission;

For write request, just return after the sector data write local cache that will write, simultaneously, regular supervision scanning local cache, by the data variation extracting section in buffer memory out, then pack, compress, be transferred to server end, by the finger daemon of server, data are really written in the image file of disk.

Compared with prior art, network virtual magnetic disk client high-efficiency buffer memory and to postpone to pre-read the sector hit rate of buffer memory for read request in wiring method quite high in the present invention, although increase slightly portion transfers data amount, but effectively decrease the frequency of transmission, evade the unfavorable factor of network delay; And for write request, just return after the sector data write local cache that will write, really be not sent to service end thus the amalgamation that is delayed, when data accumulation to certain amount or etc. really write disk again after time to be specified thus improve write performance, the unfavorable factor of circumvent network time delay, can realize having good performance, stability and adaptive network virtual magnetic disk.

Accompanying drawing explanation

Fig. 1 is network virtual magnetic disk client high-efficiency buffer memory of the present invention and the application schematic diagram postponing wiring method.

Embodiment

Refer to shown in Fig. 1, the present invention discloses a kind of network virtual magnetic disk client high-efficiency buffer memory and postpones wiring method, comprising:

For read request, when needs read certain disk sector, some sectors (being generally decided to be 64K byte, supposing that sector-size is 4k, is exactly 16 sectors) that always order pre-read is follow-up backward, and by the data in the disk sector of all readings all stored in local cache, when again reading sector, search in present local cache, if having found, just directly return, no longer pass through Internet Transmission; According to reality test, the sector hit rate pre-reading buffer memory is quite high, although increase slightly portion transfers data amount, effectively decreases the frequency of transmission, has evaded the unfavorable factor of network delay.

In write request, the large-scale address space that virtual disk needs is carried out sectional management, as, be a management unit with 64M byte, physical file set up by disk, and utilizes the File Mapping API of operating system that physical file is mapped to internal memory, access fast to provide; The structure of buffer unit is expanded, increases the record of unique and strictly increasing write mark stamp, and the interrecord structure such as sectors status flag.For in write request, the process aspect of data, adopts QuickLZ algoritic module, reads and writes the very uneven scene of this packing density done good adaptation and optimization for disk block.

In the present invention, the efficient caching technology of proposition and the delay write algorithm of optimization, for the network bandwidth, not enough or unstable network, can realize having good performance, stability and adaptive network virtual magnetic disk product.

Claims

1. network virtual magnetic disk client high-efficiency buffer memory and a delay wiring method, is characterized in that, comprising:

2. network virtual magnetic disk client high-efficiency buffer memory according to claim 1 and delay wiring method, it is characterized in that: in write request, the large-scale address space that virtual disk needs is carried out sectional management, physical file set up by disk, and utilize the File Mapping API of operating system that physical file is mapped to internal memory, access fast to provide;

The structure of buffer unit is expanded, increases the record of unique and strictly increasing write mark stamp, and the interrecord structure such as sectors status flag.

3. network virtual magnetic disk client high-efficiency buffer memory according to claim 2 and delay wiring method, is characterized in that: in write request, the process aspect of data, adopt QuickLZ algoritic module.