由于磁盘空间的客观原因，不能采用rman和expdp方式生成落地文件进行恢复或导入操作，所以最终还是决定采用impdp采用network_link方式进行数据导入，这个方式真的非常不错，并且由于impdp可以直接在服务器端后台运行，所以可以无人值守，第二天只需要检查logfile即可
此处略去创建dblink这个步骤。
Oracle$ impdp system/oracle network_link=expdp logfile=impdpXZBLOB20120331.log directory=expdp schemas=XZBLOB parallel=8
Import: Release 10.2.0.5.0 - 64bit Production on 星期六, 31 3月, 2012 16:26:55
Copyright (c) 2003, 2007, Oracle. All rights reserved.
;;;
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, Real Application Clusters, Data Mining and Real Application Testing options
Starting "SYSTEM"."SYS_IMPORT_SCHEMA_02": system/******** network_link=expdp logfile=impdpXZBLOB20120331.log directory=expdp schemas=XZBLOB parallel=8
Estimate in progress using BLOCKS method...
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 232.3 GB
Processing object type SCHEMA_EXPORT/USER
Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
. . imported "XZBLOB"."ACF_SYS_BULEX_ACFFILE" 1477 rows
. . imported "XZBLOB"."AQSIQ_WS_FILE" 1235 rows
. . imported "XZBLOB"."ACF_SYS_OPINION_ATTACH" 1844 rows
. . imported "XZBLOB"."BJYC_ISO_ATTACH" 269 rows
. . imported "XZBLOB"."YKT_FILE" 138 rows
. . imported "XZBLOB"."ISO_IMAGE_FILE" 577 rows
. . imported "XZBLOB"."AQSIQ_HUIYI_FILE" 364 rows
. . imported "XZBLOB"."XZXK_ATTACH_FILE" 14 rows
. . imported "XZBLOB"."XZ_BG_XX_XXATTACH" 13 rows
. . imported "XZBLOB"."ISO_GRAPH_FILE" 544 rows
. . imported "XZBLOB"."MAMMOTH_FS_ACFFILE" 10 rows
. . imported "XZBLOB"."ISO_CELL_FILE" 544 rows
. . imported "XZBLOB"."ITSS_HYGL" 3 rows
. . imported "XZBLOB"."MAMMOTH_PM_ACFFILE" 4 rows
. . imported "XZBLOB"."ACF_SYS_USER_SIGN_PIC_FILE" 3 rows
. . imported "XZBLOB"."ISO_FILE" 5133 rows
. . imported "XZBLOB"."ACF_SYS_TEMP_FILE" 17174 rows
. . imported "XZBLOB"."ACF_APP_BOARDFILE_UPLOADED" 19434 rows
. . imported "XZBLOB"."ACF_SYS_GWATTACH" 74986 rows
. . imported "XZBLOB"."ACF_FWGL_ZWHISTORY" 294319 rows
. . imported "XZBLOB"."ACF_SYS_SWATTACH" 180418 rows
. . imported "XZBLOB"."ARCHIVE_ATTACHMENT" 224383 rows
. . imported "XZBLOB"."ACF_APP_BAATTACH" 0 rows
. . imported "XZBLOB"."ACF_APP_BOARD" 0 rows
. . imported "XZBLOB"."ACF_APP_DZWDATTACH" 0 rows
. . imported "XZBLOB"."ACF_APP_FILE_UPLOADED" 0 rows
. . imported "XZBLOB"."ACF_APP_HELPER_UPLOADED" 0 rows
. . imported "XZBLOB"."ACF_APP_HQGDZCATTACH" 0 rows
. . imported "XZBLOB"."ACF_APP_HQGDZCIMGATTACH" 0 rows
. . imported "XZBLOB"."ACF_APP_QBATTACH" 0 rows
. . imported "XZBLOB"."ACF_APP_WORKFILE_UPLOADED" 0 rows
. . imported "XZBLOB"."ACF_APP_XFATTACH" 0 rows
. . imported "XZBLOB"."ACF_SYS_DE_ENTITY" 0 rows
. . imported "XZBLOB"."ACF_SYS_REPORT_ATTACH" 0 rows
. . imported "XZBLOB"."EXCHANGE_EDI_RECEIVE" 0 rows
. . imported "XZBLOB"."EXCHANGE_EDI_SEND" 0 rows
. . imported "XZBLOB"."WAISHI_FILE" 0 rows
. . imported "XZBLOB"."XZ_BG_LDJC_ATTACH" 0 rows
. . imported "XZBLOB"."XZ_FGZD_DOC" 0 rows
. . imported "XZBLOB"."XZ_HQ_JJ_FILE" 0 rows
. . imported "XZBLOB"."XZ_RS_DOC" 0 rows
. . imported "XZBLOB"."XZ_RS_XML" 0 rows
Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Processing object type SCHEMA_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Processing object type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Job "SYSTEM"."SYS_IMPORT_SCHEMA_02" successfully completed at 23:38:4
如上大约7个小时12分钟导入232.3GB数据，速度虽然比较慢，但是好歹夜间也不用值守，但是有一点需要注意，network是不支持long字段的迁移的，所以需要单独对long字段的表进行迁移，当前用户由于不存在long字段的表，所以没有报错，其中是有用户存在long字段的，由于数据量小，后来直接通过schema方式对该用户单独expdp/impdp操作，总体来说，对于没有足够的中转空间，并且能够容忍
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