User may fail to recover data from media failure or human mistake. Only left inconsistent datafiles that are not readable for Oracle database. Many dba did not realize that the data is still usable, but just cannot be read by Oracle instance.
PRM is that kind of tool, which can read the data direct from disk or file system without Oracle Instance. PRM can support most of Oracle database functionalities for example, cluster, lob, and partition. Why developing PRM for Oracle recovery? In this case I did open the old backup to create a full database export, I used this export to create the application user objects in a new database.
Then I did dump the data from the corrupted database using DUL and imported it into the new database. A few days ago my collegue oracle installation was damaged system tabelspace control files etc. Accidentaly Windows Server ntbackup was suspended then dumps which he has are old.
Some datafiles looks healthy is any method to restore data? In the rare 0. All data blocks have some ID of the segment they belong to. But there is a fundamental difference between V6 and V7. Data blocks created by Oracle version 6 have the address of the segment header block. Data blocks created by Oracle7 have the segment object id in the header. This is not necessarily the same order as the columns where specified in the create table statement. Cluster columns are moved to the front, longs to the end.
Columns added to the table with alter table command, are always stored last. There are two extra DUL specific data types:. DUL uses the same bootstrap procedure as the rdbms. The other tables are unloaded based on information in these first four. For each column the following statistics are gathered:. These statistics are combined and a column type is suggested. Using this suggestion five rows are unloaded to show the result. Currently known as the getlost option. There is a describe command.
During startup DUL goes through the following steps:. Starting from rdbms version 10G osd parameters are easy to configure. Typically all parameters can be used at their defaults. For pre 10G databases there is a list of known parameters in the osd wiki page list of osd Operating System Dependend parameters for almost every platform.
If your platform is not in the list you can use the suggestions below to determine the parameters. And then please inform me so I can add them to the list. The default is correct for the platform where DUL is running on.
There is no standard trick for this, the following might work on a unix system:. The number of bits in a dba used for the low order part of file number. Perform the following query:.
Structure layout in data file headers. If there is a different list this will require some major hacking and sniffing and possibly a major change to DUL. Email Bernard. Duijnen oracle. You can add an additional byte offset in control. The format of the control has been extended. Currently there are three types of specifications in the DUL control file. Each entry on a separate line.
The asm disks must precede the asm files. Its generally sufficent to specify the device name. All properties are automatically retrieved by header inspection. The full syntax is only needed when header inspection is impossible, that is for disks with corrupt headers. The syntax is:. A block index is a way to access oracle blocks on corrupt file systems. In general a corrupt file system is not wiped out, its not empty. Due to the specific layout of oracle blocks it is possible to datablocks an store their location in the block index.
See also the create block index command. Each entry can contain a part of a datafile. The smallest unit is a single data block. This way it is possible to split datafiles that are too big for DUL in parts where each part is smaller than 2GB. In general it is sufficient to specify the file name.
Even for a single block. If compatible is 10 or higher the file numbers and the tablespace numbers will be read from the file header. If the specified details are different from the file header DUL will give a warning but use your specification. This is to be able to unload files with a corrupted header block. For debugging it is possible to dump the file header. The optional extra leader offset is an extra byte offset, that will be added to all lseek operations for that datafile.
This makes it possible to skip over the extra 4k block for some AIX raw devices, or the extra 64K on Tru64 on raw devices. This looks familiar, use the above information and your knowledge of the emp table to compose:. This can generate output similar to below.
Normally this should not happen since you should create a demo database and check this via the DUL documented in html page query. The second number, the block number, is correct.
This may create output similar to below, but many other flavours are possible. In this case we are a fixed number of blocks off. The file number is correct. The difference in the block numbers is constant. This may generate output similar to the following:. The date lock is 30 days. This version basically will become invalid by the time of November 1.
DUL 10 English version of user manual:. The following is the download link DUL 10, but because of the lock, it will fail regularly.
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