(( CC me the replies, as I'm not subscribed to LKML ))
Hi!
It is a good idea IMO to flush the write cache of storage devices
at shutdown and other critical moments.
I browsed through linux-2.4.1 and see no use of the SYNCHRONIZE CACHE
SCSI command ( curiously it is defined in several other files
besides include/scsi/scsi.h , grep returns :
drivers/scsi/pci2000.h:#define SCSIOP_SYNCHRONIZE_CACHE 0x35
drivers/scsi/psi_dale.h:#define SCSIOP_SYNCHRONIZE_CACHE 0x35
drivers/scsi/psi240i.h:#define SCSIOP_SYNCHRONIZE_CACHE 0x35
)
I couldn't find evidence to the use of the equivalent ATA command either
( FLUSH CACHE , command code E7h ).
Also add ATAPI to the list. ( and all other interfaces. I checked just SCSI
and ATA )
Loosing data at powerdown due to write caches have been reported,
so this is no a theoretical problems. Also the journaled filesystems
are safe only in theory if the journal is not stored on non-volatile
memory, which is not guarantied in the current kernel.
What is the official word on this issue ?
I think this is important to the "enterprise" guys, at the least.
Sincerely,
david
PS: CC me , as I'm not subscribed to LKML
-- David Balazic -------------- "Be excellent to each other." - Bill & Ted - - - - - - - - - - - - - - - - - - - - - - - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:19 EST