快上网专注成都网站设计 成都网站制作 成都网站建设
成都网站建设公司服务热线:028-86922220

网站建设知识

十年网站开发经验 + 多家企业客户 + 靠谱的建站团队

量身定制 + 运营维护+专业推广+无忧售后,网站问题一站解决

RMAN备份压缩你了解多少-创新互联

1、RMAN备份默认已经进行压缩
1)不用的块压缩
When employing unused block compression, RMAN skips reading, and backing up, any database blocks that are not currently allocated to some database object. This is regardless of whether those blocks had previously been allocated.

So if a database table is dropped, RMAN will not back up the space that was occupied by that table until new objects are created in that space.

Unused block compression is used automatically when the following conditions are true:

The COMPATIBLE initialization parameter is set to 10.2 or higher.

There are currently no guaranteed restore points defined for the database.

The data file is locally managed.

The data file is being backed up to a backup set as part of a full backup or a level 0 incremental backup.

The backup set is created on disk, or Oracle Secure Backup is the media manager.

2)空块压缩
When employing null block compression, RMAN omits from its output any block that has never contained data.

Null block compression is always used with level 0 or full backups that are created in backup set format.

小结:

1)这样我们可以解释了,为什么全备份输入的大小和输出的大小不一致了。
2)归档日志输入输出大小一致,说明不会做压缩,只有全归档日志备份。

START_TIME       INPUT_TYPE    STATUS     INPUT_SIZE   DEVICE_TYP OUTPUT_SIZE  TIME_TAKEN IN_SPEED   OUT_SPEED
---------------- ------------- ---------- ------------ ---------- ------------ ---------- ---------- ----------
2018-10-04 12:01 ARCHIVELOG    COMPLETED      2.58G    SBT_TAPE       2.58G    00:03:06      14.20M     14.20M
2018-10-04 13:00 ARCHIVELOG    COMPLETED      2.50G    SBT_TAPE       2.50G    00:03:24      12.54M     12.55M
2018-10-04 18:01 ARCHIVELOG    COMPLETED      2.17G    SBT_TAPE       2.17G    00:03:15      11.39M     11.39M
2018-10-04 19:01 ARCHIVELOG    COMPLETED      2.11G    SBT_TAPE       2.11G    00:03:29      10.33M     10.34M
2018-10-05 01:01 DB FULL       COMPLETED    686.17G    SBT_TAPE     565.61G    00:37:05     315.79M    260.31M
2018-10-05 06:00 ARCHIVELOG    COMPLETED      1.50G    SBT_TAPE       1.51G    00:03:14       7.94M      7.95M
2018-10-05 07:01 ARCHIVELOG    COMPLETED    992.30M    SBT_TAPE     993.00M    00:02:59       5.54M      5.55M
2018-10-05 12:01 ARCHIVELOG    COMPLETED      2.41G    SBT_TAPE       2.41G    00:03:14      12.73M     12.74M

另外有需要云服务器可以了解下创新互联cdcxhl.cn,海内外云服务器15元起步,三天无理由+7*72小时售后在线,公司持有idc许可证,提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案,具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势,专为企业上云打造定制,能够满足用户丰富、多元化的应用场景需求。

成都创新互联一直在为企业提供服务,多年的磨炼,使我们在创意设计,网络营销推广到技术研发拥有了开发经验。我们擅长倾听企业需求,挖掘用户对产品需求服务价值,为企业制作有用的创意设计体验。核心团队拥有超过十余年以上行业经验,涵盖创意,策化,开发等专业领域,公司涉及领域有基础互联网服务成都棕树机房app软件定制开发、手机移动建站、网页设计、网络整合营销。
分享题目:RMAN备份压缩你了解多少-创新互联
网页网址:http://6mz.cn/article/ggecd.html

其他资讯