High Availability MySQL Cookbook phần 4

Đây là những tập tin được lựa chọn Node 1 (trong đó có một nodeID của 3 theo sản lượng khách hàng quản lý trước đó). Node 2 sẽ có chính xác cùng một tập tin, sự khác biệt duy nhất là nodeID (4). Tương tự có thể được nhìn thấy trên hai nút lưu trữ khác như sau: | Chapter 2 These are the files that are on nodel which had a nodelD of 3 according to the management client output earlier . root@node1 cd var lib mysql-cluster BACKUP root@node1 BACKUP ls -lh total drwxr-x----- 2 root root Jul 23 22 31 BACKUP-1 root@node1 BACKUP cd BACKUP-1 root@node1 BACKUP-1 ls -lh total 156K -rw-r--r-- 1 root root 126K Jul 23 22 31 -rw-r--r-- 1 root root 18K Jul 23 22 31 -rw-r--r-- 1 root root 52 Jul 23 22 31 Node2 will have exactly the same files the only difference is the nodeiD which is 4 . The same can be seen on the other two storage nodes as follows root@node2 cd var lib mysql-cluster BACKUP BACKUP-1 root@node2 BACKUP-1 ls -lh total 152K -rw-r--r-- 1 root root 122K Jul 23 22 31 -rw-r--r-- 1 root root 18K Jul 23 22 31 -rw-r--r-- 1 root root 52 Jul 23 22 31 The default location for backups is the BACKUP subfolder in DataDir however the parameter BackupDataDir in file can be specified to set this to something else and it is best practice to use a separate block device for backups if possible. For example we could change the NDBD_DEFAULT section to store backups on mnt disk2 as follows ndbd default DataDir var lib mysql-cluster BackupDataDir mnt disk2 NoOfReplicas 2 MySQL Cluster Backup and Recovery There s more. There are three tricks for the initiation of online backups Preventing commands hanging The START BACKUP command by default waits for the backup to complete before returning control of the management client to the user. This can be annoying and there are two other options to achieve the backup START BACKUP NOWAIT This returns control to the user immediately the management client will display the output when the backup is completed and you can always check the cluster management log. This has the disadvantage that if a backup is going to fail it is likely to fail during this brief initial period where the management .