Centos 5.x, ext3, md raid1
As I do not have UPS for all machines, and I most often use md raid (level 1), I would like to turn the write cache off for all of my server discs. But how?
Below is what I have already found out:
On the page
http://lwn.net/Articles/350072/
I read that I could do this by running hdparm -W0 /dev/sdX , but when I say hdparm -h, it says that the -W option is “dangerous”.
This is the current hdparm output for one of my raid discs:
[root@mail etc]# hdparm /dev/sda /dev/sda: IO_support = 0 (default 16-bit) readonly = 0 (off) readahead = 256 (on) geometry = 38913/255/63, sectors = 625142448, start = 0
(BTW, here is a hdparm tutorial for Ubuntu:
http://ubuntuforums.org/showthread.php?t=16360 )
And when I get this done, then how can I make the setting last over the next bootup?
Regards, Jussi P.S. Do you really have to quote the whole thread when you respond?