11/17/2007
Data Test Program (dt)
40
False Data Corruptions?
nPremature end of file on writes can lead to false data compare errors with random I/O, since more data may get read than written.  In general, dt expects to read as much as is written.  Note: Correct for raw I/O, need to fix for file system I/O! L
n
ushaix11# dt of=/tmp/dt.data bs=32k iotype=random capacity=250m limit=1g \
u stats=brief enable=edebug dlimit=32
udt: WARNING: Record #4223, attempted to write 32768 bytes, wrote only 28160 bytes.
udt: End of media detected, count = -1, errno = 28 [file #1, record #4224]
uEnd of Write pass 0/1, 270263 blocks, 131.964 Mbytes, 4223 records, errors 0/1, elapsed 00m05.05s
u
udt: Error number 1 occurred on Wed May 16 16:12:36 2007
udt: Elapsed time since beginning of pass: 00m04.27s
udt: Elapsed time since beginning of test: 00m09.32s
udt: Data compare error at byte 28160 in record number 4223
udt: Relative block number where the error occurred is 154232, position 78966784
udt: Data expected = 0x39, data found = 0, byte count = 32768
udt: The correct data starts at address 0x20005b18 (marked by asterisk '*')
udt: Dumping Pattern Buffer (base = 0x20005b18, offset = 0, limit = 4 bytes):
u
u0x20005b18 *39 9c c3 39
u
udt: The incorrect data starts at address 0x2000de00 (marked by asterisk '*')
udt: Dumping Data Buffer (base = 0x20007000, offset = 28160, limit = 32 bytes):
u
u0x2000ddf0  39 9c c3 39 39 9c c3 39 39 9c c3 39 39 9c c3 39
u0x2000de00 *00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
uEnd of Read pass 1/1, 270272 blocks, 131.969 Mbytes, 4223 records, errors 0/1, elapsed 00m04.27s
u/tmp/dt.data Totals: 540535 blocks, 263.933 Mbytes, errors 0/1, passes 1/1, elapsed 00m09.32s
ushaix11#