First, the introduction
With the rapid development of computer technologies, server technology is also constantly maturing, it can be said that the server is taking a step at a time before the need for minicomputer and even large and medium-sized machines can achieve the task. Current server technology hotspots are: Irisc and CISC technology, processor technology, multiprocessor technology (AMP technology, SMP Technology, MPP Technology, coma Technology, cluster technology and NUMA technology), SCSI interface technology, intelligent I/O technology, fault-tolerant technology, disk array technology, Hot-swappable technology, dual-machine hot backup.
The so-called dual-machine hot backup refers to the system on the host and hard disk, communication lines and other core equipment, the use of dual-computer backup, when the system is normal when the host work, and every time the system is automatically detected, if the problem found, the system can automatically switch to the backup machine to continue to work, to ensure that the system does not affect the normal operation.
Because computer software and hardware will inevitably fail, and these failures can bring great losses to enterprises, so for modern enterprises, the use of dual-computer hot backup system to provide timely and reliable information and services has become a necessary measure to ensure the security of enterprise data.
In the process of building intranet network of Xinhua pharmaceutical group, taking into account the security of enterprise data and the continuity of enterprise production, the paper makes use of Windows NT 4.0 (PACK6) and ROSE HA for the topological structure of the network. , SQL SERVER7.0 realizes the dual-computer hot backup system of ERP database server.
Second, the system scheme design
1 Scenario Background
Xinhua Pharmaceutical Group Intranet Network is based on Gigabit Ethernet technology to achieve a large enterprise internal network. Its backbone network employs Gigabit Ethernet technology, and the low-end uses hundred Gigabit Ethernet technology to extend to desktop workstations. The whole network is connected with more than 500 workstations and 12 servers, the design goal is to ensure the implementation of ERP projects and access to the Internet. Its ERP project is implemented by Shenzhen Kingdee software company, the database adopts SQL SERVER 7.0 and the operating system uses Windows NT 4.0 (PCAK6). and need to realize the dual-machine hot backup function is the core equipment in ERP project-database server.
2 System Structure Analysis
(1) System mode
The current dual-computer hot standby system in the database services are mainly the following two modes to choose from:
Host and from the machine all the equipment completely independent, the host from the machine have a completely independent database system, from the computer database system to provide a backup of the host, the workstation in the submission of tasks, while submitting to the host and from the machine. The host and from the machine has heartbeat monitoring, once from the machine found the host heart stopped, immediately announced the takeover of the host. There will be about 1 minutes of downtime during the takeover process.
The host and the machine have separate operating systems and independent data services, but the data resides on the same external magnetic consolidation device. Host and from the computer Data Services synchronization, host and from the machine has heartbeat monitoring, once from the machine found the host heartbeat stopped, immediately announced the takeover of the host. The take-over process has no downtime.
We take into account the continuous production process of the Xinhua pharmaceutical Group final decision to adopt the second option. The shared external disk device uses a escort DA6000 disk array.
(2) System software composition
Operating system: WINDOWS NT 4.0 (Pcak 6.0)
Database: SQL SERVER 7.0
Dual-Machine fault-tolerant software: ROSE HA
(3) System hardware composition
Server: HP LH4 Server
CPU: Pentium Zhi Qiang (Intel server dedicated CPU), dual CPU
Memory: 512M ECC server memory
Hard drive: raid1/18g*2
Shared disk devices: ESCORT DA6000 disk array
ULTRA Wide/ultra 2/fibre Channel
Supports parallel I/O and command queuing
raid5+ Global Backup/80g*5
(4) System topological structure
As shown in the following illustration:
Third, the system realizes the step
1. Disk array cabinet settings:
A total of 5 Seagate 80G SCSI hard drives, 3 of which are used for RAID 5, a hot standby for RAID5, and one for global provisioning, thus maximizing data security. Connect the disk array cabinet with the two HP servers through the SCSI cable.
2. Installation of the operating system:
Install two separate Windows NT 4.0 operating systems on two HP servers, and then install PCAK6.0 and Windows DATA access patches. Divide the local hard disk into two logical disks: C and D, and use the shared disk on the disk array cabinet as E disk to store the SQL Server data.
Note: Any data other than SQL Server data is not allowed on disk E, and the existence of the file Recycle Bin is not allowed because it affects the sharing of data.
Allocate any one of them for the host, host name XHHOTSP1, and another as from the machine, from the machine name XHHOTSP2.
Install two network cards on the host, one piece as a private network directly connected to the other machine corresponding network card, used to monitor the heartbeat of each other. The NIC loads the TCP/IP protocol with the address defined as 10.10.10.1. Another piece connected to the public network to provide services, its IP address is defined as 192.168.0.10, the same installation of two network cards from the machine, the IP address is defined as: 10.10.10.2 and 192.168.0.11.
A connection is established between the COM1 of the two servers via a serial port (rate of 9600bps).
3. Installation of the database:
First install the SQL Server database on the host, choose to install the database system files under the D:\SQL7.0 path when selecting the system path, install the data portion under the shared disk E:\SQLDATA path provided by the raid cabinet, and then install the SQL Server database from the computer. The database system files are also installed on the D:\SQL7.0 path from the machine's own disk, and the data portion is installed under the shared disk E:\SQLDATA path provided by the disk array cabinet, overwriting the data written by the original host when the database is installed.
Note that you want to block the automatic startup of the database service.
4. Installation of ROSE ha:
First install the Rose HA Program on the host and from the machine, then go to the Rose Ha Monitoring program of the host and make the two-machine matching settings:
Monitor each other's heartbeat through the serial port.
10.10.10.2 Monitor the heartbeat of each other through the IP address of the other private network card.
An alias sharing service is established between two computers, giving XHHOTSP1 and XHHOTSP2 a drift hostname xhhotsp.
Establish a volume shared service between two machines, giving XHHOTSP1 and XHHOTSP2 a shared disk space E, which is provided by a disk array cabinet.
The establishment of IP sharing services between the two computers, the two machines public network card 192.168.0.10 and 192.168.0.11 IP address of the external shielding, with a drift address 192.168.0.50 replaced.
Build SQL Server, SQL Server AGENCY, distribute Transanction shared services based on the shared services described above and take over the automatic startup of SQL Server by Rose ha.
5. Reboot the host, from the machine.
At this point, the dual-machine hot standby system configuration completed. The system is usually provided by the host to provide database services, from the machine in a dormant state. From the machine through the COM1 and internal private network at any time to monitor the heartbeat of the host, when the host heartbeat is not monitored to announce the takeover of all tasks, and alarm.
Iv. concluding remarks
The system can tolerate the error of two hard drives at the same time, and there is no time slot in the host fault, there is no downtime; in terms of speed, the Ultra 2 standard provided by the disk array cabinet guarantees fast access to SQL Server data. Through the fault-tolerant test and the actual operation for more than one year, it is proved that the dual-machine hot standby system for the ERP database server designed by Xinhua Medicine Group meets the design requirements in terms of safety, speed and so on.
