4
Chapter
Data Consistency, Recovery,
and Migration
In This Chapter .................... 4-5
Consistency Checking .................. 4-6
Using the tbcheck Commands.............. 4-6
tbcheck -cr ................... 4-7
tbcheck -cc ................... 4-7
tbcheck -ce ................... 4-7
tbcheck -cI ................... 4-8
tbcheck -cD ................... 4-8
Using the OnLine Message Log ............. 4-8
Setting Consistency-Checking Variables .......... 4-9
GCORE .................... 4-10
DUMPCORE .................. 4-11
DUMPSHMEM ................. 4-11
DUMPDIR ................... 4-12
Recovering from Corruption .............. 4-12
Mirroring ...................... 4-14
Beginning..................... 4-15
Processing .................... 4-16
Recovery ..................... 4-17
Ending...................... 4-17
OnLine Logging Overview ................ 4-18
Dbspace Logging .................. 4-19
Blobspace Logging ................. 4-22
Operations Logging ................ 4-24
Operations Rollback................ 4-24
Blob Restoration ................. 4-25