使用RMAN进行数据迁移

使用RMAN进行数据迁移

1.查看SCN,然后备份数据库

run{
?allocate channel c1 type disk;
?allocate channel c2 type disk;
?allocate channel c3 type disk;
?allocate channel c4 type disk;
?allocate channel c5 type disk;
?sql 'alter system archive log current';
?backup database tag 'db0'? include current controlfile plus archivelog;
?release channel c1;
?release channel c2;
?release channel c3;
?release channel c4;
?release channel c5;
?}

备份的文件249G,备份用时20分钟

2.将备份传输至目标服务器 (53分钟)

将数据库启动至nomount
?restore spfile to '/xxxx/spfilemvbox.ora' from '/xxxx/2015_06_11/o1_mf_nnsnf_DB0_bqky8s7r_.bkp';

还原控制文件
shutdown abort;
?startup mount;
?restore controlfile from '/xxxx/2015_06_11/o1_mf_ncnnf_DB0_bqky8pq9_.bkp';
?sql 'alter database mount';

挂载备份
catalog start with '/xxxx/2015_06_11';

还原数据库
run{
?allocate channel c1 type disk;
?allocate channel c2 type disk;
?allocate channel c3 type disk;
?allocate channel c4 type disk;
?allocate channel c5 type disk;
?restore database;
?release channel c1;
?release channel c2;
?release channel c3;
?release channel c4;
?release channel c5;
?}

还原数据库用时 30分钟

4.在目标服务器进行数据库恢复(业务实际停机时间)
首先,业务停机
?然后查看当前的SCN
?select to_char(CURRENT_SCN) from v$database;

备份归档日志
sql 'alter system archive log current';
?run{
?allocate channel c1 type disk;
?allocate channel c2 type disk;
?allocate channel c3 type disk;
?allocate channel c4 type disk;
?allocate channel c5 type disk;
?backup archivelog all tag 'arch0';
?release channel c1;
?release channel c2;
?release channel c3;
?release channel c4;
?release channel c5;
?}

因为在迁移之前,清空过归档日志,所以归档日志只是从备份开始到现在的这段时间
?日志量不大,10分钟以内就可以完成 备份和传输

?清空归档日志的命令(delete noprompt archivelog all;)

挂载归档日志
catalog start with '/xxxx/2015_06_11';

进行不完全恢复,
set until scn xxx
这个数字就是备份归档日志之前查看的SCN

?run{
?shutdown immediate;?
?startup mount;?
?set until scn? 79377202898;?
?allocate channel c1 type disk;
?allocate channel c2 type disk;
?allocate channel c3 type disk;
?allocate channel c4 type disk;
?allocate channel c5 type disk;
?recover database;
?release channel c1;
?release channel c2;
?release channel c3;
?release channel c4;
?release channel c5;
?}

恢复用时11分钟（应用归档日志从10:40至14:39,4个小时）

alter database open resetlogs;

迁移完成.

比对MySQL的不完全恢复
?可以发现
MySQL先恢复,再应用binlog,最后还原
?他恢复的时间比较短,主要的时间是应用binlog（每恢复一小时的binlog需要15分钟）,最后的还原不需要时间(直接改datadir..)

而Oracle,先还原再恢复
?还原的时间比较长(30分钟),而恢复的时间比较短(每推进一小时的数据需要2到3分钟)
所以,在备份的服务器,保持一个最近还原的备份很重要..最起码会节省30分钟的还原时间..

--------------------------------------推荐阅读 --------------------------------------

--------------------------------------分割线 --------------------------------------