Hi!
>>>>> "Mike" == Mike Black <[EMAIL PROTECTED]> writes:
Mike> Here's a strace -r on IDE:
Mike> 0.001488 write(3, "\214\1\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000516 fdatasync(0x3) = 0
Mike> 0.001530 write(3, "\215\1\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000513 fdatasync(0x3) = 0
Mike> 0.001555 write(3, "\216\1\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000517 fdatasync(0x3) = 0
Mike> 0.001494 write(3, "\217\1\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000515 fdatasync(0x3) = 0
Mike> 0.001495 write(3, "\220\1\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000522 fdatasync(0x3) = 0
Mike> Here it is on SCSI:
Mike> 0.049285 write(3, "\3\0\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000689 fdatasync(0x3) = 0
Mike> 0.049148 write(3, "\4\0\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000516 fdatasync(0x3) = 0
Mike> 0.049318 write(3, "\5\0\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> 0.000516 fdatasync(0x3) = 0
Mike> 0.049343 write(3, "\6\0\0\0Blah Blah Blah Blah Blah Bla"..., 56) = 56
Mike> Looks like a constant 50ms delay on each fdatasync() on SCSI vs .5ms for
Mike> IDE. Maybe IDE isn't really doing a sync?? I find .5ms to be a little too
Mike> good.
I wonder from where the fdatasync() is comming; MySQL is not doing
those (if you are not running mysqld with --flush)
Mike> I did this on 4 different machines with different SCSI cards (include RAID5
Mike> and non-RAID), disks, and IDE drives with the same behavior.
Regards,
Monty
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