BIO_FLUSH on twe driver. Why is it not there?

Artem Kuchin matrix at itlegion.ru
Fri Nov 2 03:31:40 PDT 2007


>> > However, twe is working via scsi subsystem and the authour of gjournal
>> > said somewhere that he has had implemeneted BIO_FLISH for scsi and he
>> > specifically mentioned that he has tested twe and twa and they both
>> > support BIO_FLUSH.
>> 
>> twa(4) uses CAM, but twe(4) doesn't (and never has).
>
>That was my mistake. Someone told me (I think it was jhb@), that twe(4)
>turns off write cache automatically when there is no battery, so
>BIO_FLUSH isn't really needed and if there is a battery, it also isn't
>really needed. It would be nice to hide the warning in this case
>somehow, but for now you should be safe by simply ignoring the warning.

Um.. If battry is not installed write can be enabled easily.

Here is my setting:

Unit Write Cache (Controller ID 0)
  Unit 2  [RAID 1] Enabled 

Is your phrase "it also isn't really needed'  related to this case too?
'Cause you said if BIO_FLUSH is not there and write cache is bigger than
gjorunal's cache there could be trouble. Cache on my controller is 64MB,
what;s the size of gjournal's cache?

--
Artem


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