> -----Original Message----- > From: Keld Jørn Simonsen [mailto:keld@xxxxxxxx] > Sent: Tuesday, October 14, 2008 9:38 AM > To: David Lethe > Cc: Martin K. Petersen; Billy Crook; Justin Piszcz; Bill Davidsen; Neil > Brown; Linux RAID > Subject: Re: Distributed spares > > On Tue, Oct 14, 2008 at 08:30:00AM -0500, David Lethe wrote: > > > > > > Good to know. Could yo tell me if this is actually true for normal > > state-of-the art SATA disks, or only true for more expensive disks? > > Do you have a good reference for it. > > > > > > read the manual for any disk drive... They go into error detection, > correction recovery algorithms and capability in great detail. > > I don't get any manual when I buy a disk. Maybe you do - as you are > doing raid systems for your work. > > I will see if I can dig upsome manuals on the net for the disks I have, > just to have some sense of what is state-of-the art. > > best regards > keld The manuals are all online. There are typically several to choose from. Installation Manuals are standard, but are pretty worthless. Look for programming/interface specification manuals. They are not always online where you can find them easy, it depends on the manufacturer. They're typically several hundred pages long. Also firmware specifications go into algorithms in great detail, but unless you have NDA then you won't get them. (And people like me who have NDAs, are not allowed to share them). In any event, manuals are important. They reveal such things like the duty cycles for most of the Consumer class disks you get with PCs & at the retails are 2400 hours. i.e, 100 days x 24 hrs/day, Unlike enterprise class disks that are rated for 24x7x5 years. (So disks are not all the same). Enterprise class drives have more ECC bits and smarter algorithms for automated recovery, and extended online/offline diagnostic capability. Some drives also have a limited number of start/stop cycles. Choose disks wisely! David -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
