Exadata X8M-2 & PCA X8-2 -- Part 3 Migration / add-on - XTTS may fail ORA-17503: ksfdopn:2 Failed to open file

We are continuing our journey on Exadata and PCA migration, and here is the tip of the day;

Although XXTS know reached the 4th version, 4th generation, there are still some cases that it can't handle, and there are still some bugs that we need to pay attention to. Especially when your source database consists of a high number of datafiles, multiple incremental backups to restore and when you use a high degree of parallelism.

Well.. you may end up with the following; while trying to roll forward your target database.. I mean, when applying incremental backups to the datafile copies on the destination system ... (Remember-> we use RMAN incremental backups for accelerating our XXTS migation operations) 

-- Main Document: V4 Reduce Transportable Tablespace Downtime using Cross Platform Incremental Backup (Doc ID 2471245.1)

So, you may end up with;

ORA-17503: ksfdopn:2 Failed to open file +DATAC1/ERM/DATAFILE/erm_732.dbf

ORA-19625: error identifying file +DATAC1/ERM/DATAFILE/erm_732.dbf

ORA-15173: entry 'erm_732.dbf' does not exist in directory 'DATAFILE'

Don't push yourself hard to find your workaround, because there are issues associated with the following bugs ->

bug 31620676: V4 XTTs RECOVERY FAILS WITH MULTIPLE INCREMENTAL BACKUPS

Bug 31054229 : XTTS V4 CREATING INCORRECT RECOVER COMMAND -- note that, this bug currently being investigated by Oracle.. Status : 11 - Code/Hardware Bug (Response/Resolution). Escalated

Luckily, we have workarounds documened in MOS and the ones given in the following MOS document clearly help ->

V4 XTTs: Restore Returns Errors (ORA-19625 or ORA-19641) With Large Number of Datafiles (Doc ID 2689397.1)

We just do some tricks in res.txt and apply one incremental at a time to these both bugs...

However; this workaround alone may not be sufficient in certain cases, where you have a high degree of parallelism. I mean;

It is also recommended to use a lower degree of parallelism in xtt.properties to prevent those RMAN errors . In our case, we concluded that XTTS can not manage 128 parallel thread/workers so, we decreased it to a lower value (32) .

This was a real life case and I wanted to share it with you.. I hope it helps..