http://www.sybase.com/detail?id=1040311 The techdoc describes that data may be lost due to os buffering of the block devices (raw devices) if the machine goes down. Unfortunately, it doesn’t indicate whether "shutdown with nowait", "kill -9", "kill -15" or "kill -4" also result in data loss because of the os buffering.
I asked Sybase techsupport to update the techdoc and the cr.
PSE has updated the CR 406473 description
ASE 12.5.1 or later versions prior to 12.5.3 ESD #5 and version 15.0
treat block device the same as raw device. ASE assumes all writes
have been committed to disk, while the modified pages may be retained
in the OS kernel cache. In the event of a power failure or other
system crashes, the cached modifications may be lost leading to
Using a shutdown with nowait by itself would not cause an inconsistency.
Recovery would of course take more time during the next startup if we
do a ‘shutdown with nowait’ though.
There is also a possibility that if theres a system crash or a power
outage during shutdown, it could lead to a data loss. However, note
that a system crash has to occur for us to encounter
this sort of situation.