[Basics]
1, common cluster technology generally include: high availability clustering, load balancing clusters, high performance computing clusters .
2, server cluster system, the popular talk is to multiple servers connected via fast communication link .
3, server cluster advantages: high scalability, high availability and manageability .
4, to the member server to a domain controller is the command dcpromo.
5, set up when you create a virtual SQL Server cluster disk, the disk is formatted as NTFS.
. 6, WEB- failover cluster configuration process clusweb.vbs need to copy each node to the% systemroot% \ system32 under \ inetsrv.
7, service or application configuration web- failover is added to generic script .
8, service or application configuration SQL- failover is added to DTC Distributed Transaction Coordinator
9, the similarity NLB are used define the relationship between the host and source members NLB cluster members .
10, comprises a similarity NLB -free, single and three networks .
11, the characteristics of the NLB similarity "None".
12, NLB operation mode of unicast and multicast modes.
13, keepalived based VRRP protocol for the realization of the foundation.
14, keepalived main core, check and VRRP module
15, LVS 3 modes of operation is divided into: the DR, the NAT, TUN .
16, refers to a split brain:
After the backup host can not receive the master server packets will switch to be master. If the communication line between the emergence of their problems, can not receive each other's anchor notice, but two nodes are in a state of actual work, which makes it binding force two nodes are master virtual IP, leading to unpredictable results this is split brain.
Brain Solutions cracking:
1) add more detection methods, such as redundant core lines (two network cards do health monitoring), ping each other, etc., to minimize split brain occurs (palliative)
2) algorithm guarantees, such as the use voting mechanism
3) set up an arbitration mechanism, the two sides are not reliable, such as enabling shared disk lock, ping gateway
Experimental :( failover --SQL)
(1) set the basic link
(2) DC installation on Active Directory: Run in the Start cmd, open input dcoromo, click Run as administrator, will promote a member server to a domain controller server
(3) mounted storage server: Add three hard disks, composed of a RAID5; install the software update; iscsi software installation: ISCSI_Software_Target_33.iso added to the CD-ROM drive, the installation.