I neglected to mention, this is on FreeBSD 4.6 -STABLE as of August 10th. -Antony
Antony Mawer wrote: > After reading about the potential dangers assocaited with enabling the > write cache on ATA drives in combination with softupdates, I've recently > added the following to /boot/loader.conf: > > hw.ata.wc="0" > > Once booted, running sysctl confirms that this is set: > > [root@gibson] ~# sysctl hw.ata.wc > hw.ata.wc: 0 > > However, looking at the atacontrol cap output, it appears that write > caching is still enabled on both ATA drives (see below). Can I trust the > information from atacontrol cap to be accurate? And if so, why is write > caching enabled when the sysctl is explicitly set to off? The system was > rebooted after adding the change to loader.conf to allow it to take > effect... > > I'm not overly worried by sacrificing some performance for potentially > increased safety gains as disabling write caching involves... > > Any thoughts? > -Antony > > [atacontrol output below] > > > > [root@gibson] ~# atacontrol cap 2 0 > ATA channel 2, Master, device ad4: > > ATA/ATAPI revision 5 > device model ExcelStor Technology CT210 > firmware revision ES4CA53D > cylinders 16383 > heads 16 > sectors/track 63 > lba supported 20040450 sectors > lba48 not supported > dma supported > overlap not supported > > Feature Support Enable Value Vendor > write cache yes yes > read ahead yes yes > dma queued no no 0/00 > SMART yes no > microcode download yes yes > security yes no > power management yes yes > advanced power management no no 0/00 > automatic acoustic management no no 0/00 0/00 > > > [root@gibson] ~# atacontrol cap 3 0 > ATA channel 3, Master, device ad6: > > ATA/ATAPI revision 5 > device model QUANTUM FIREBALLlct20 10 > firmware revision APL.0900 > cylinders 16383 > heads 16 > sectors/track 63 > lba supported 20044080 sectors > lba48 not supported > dma supported > overlap not supported > > Feature Support Enable Value Vendor > write cache yes yes > read ahead yes yes > dma queued no no 0/00 > SMART yes no > microcode download yes yes > security yes no > power management yes yes > advanced power management no no 0/00 > automatic acoustic management yes no 0/00 0/00 > > > To Unsubscribe: send mail to [EMAIL PROTECTED] > with "unsubscribe freebsd-stable" in the body of the message To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-stable" in the body of the message
