2009-08-23-08.48.15.178878+540 I22649A376 LEVEL: Info
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgRecreateNextExt,
probe:2000
DATA #1 : <preformatted>
Expected log file S0111856.LOG not in active log path.
Logger will attempt to recreate it.

2009-08-23-08.55.57.455189+540 E23026A517 LEVEL: Warning (OS)
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, oper system services, sqloopenp, probe:80
MESSAGE : ZRC=0x870F0016=-2029060074=SQLO_SHAR "File sharing violation." DIA8519C A file sharing violation has occurred, filename was "".
CALLED : OS, -, open
OSERR : ETXTBSY (26) "Text file busy"
DATA #1 : File name, 25 bytes
/DSCTIA2/LOG/S0111856.LOG

2009-08-23-08.55.57.468250+540 I23544A396 LEVEL: Error
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgolf, probe:220
RETCODE : ZRC=0x870F0016=-2029060074=SQLO_SHAR "File sharing violation."
DIA8519C A file sharing violation has occurred, filename was
"".

2009-08-23-08.55.57.468410+540 I23941A452 LEVEL: Error
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgolf, probe:220
MESSAGE : Filename :
DATA #1 : Hexdump, 25 bytes
0x0FFFFFFFFFFFD680 : 2F44 5343 5449 4132 2F4C 4F47 2F53 3032
/DSCTIA2/LOG/S02
0x0FFFFFFFFFFFD690 : 3732 3334 382E 4C4F 47
72348.LOG

2009-08-23-08.55.57.468954+540 I25764A314 LEVEL: Error
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgole, probe:1710
MESSAGE : Error -2029060074 opening database log extent 111856:

2009-08-23-08.55.57.469176+540 E26486A477 LEVEL: Severe
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgWriteToDisk,
probe:1030
MESSAGE : ZRC=0x870F0016=-2029060074=SQLO_SHAR "File sharing violation." DIA8519C A file sharing violation has occurred, filename was "".
DATA #1 : <preformatted>
Error while writing to log file S0000000.LOG

2009-08-23-08.55.57.469807+540 I28165A287 LEVEL: Severe
PID : 606546 TID : 1 PROC : db2loggw
(DSCTIA2) 0
INSTANCE: inst2 NODE : 000
FUNCTION: DB2 UDB, data protection services, sqlpgasn2, probe:4330
MESSAGE : Logging can not continue.

After that the database got damaged and instance went down.

Our DBA group understand that cause is some process had a lock on an active log S0111856.LOG ,
When db2 tried to write to the log, it failed to open the file with error 'ETXTBSY'. This is returned by OS.
Hence log file can't be written and db mark damage.
We can find the locking process by fuser or lsof.

We would like to know how to prevent this in future?
("File sharing violation." - ETXTBSY )

Prevent the locking process to be run at all or to run only on already archived log files.

Knut,
my question is "How to prevent that error in future"

That obviously depends on what process locks the active log file.

If it were a DB2 process, it is a defect and you should open a PMR with IBM support. If it is your own tool or a 3rd party software, fix that tool. In that case it is really not a DB2 problem as n_i implies.