low-level format before install?

[Roland Smith]

On Tue, Apr 07, 2009 at 03:15:59PM -0400, John Almberg wrote:
> Well, I've got real problems with that database server that lost  
> power over the weekend. We reloaded FreeBSD from scratch and then  
> reinstalled mysql, and pf. I loaded up my database and switched over  
> all my customer's websites. The database server ran fine for about 2  
> minutes, and then died. At the moment, I can't even ssh into the  
> machine, although they can get into it using a keyboard/monitor at  
> the data center. In other words, sshd is not working.
> 
> I am now wondering what kind of format the FreeBSD install process  
> does by default, and if it is possible to do a low level format,  
> first, to block out any bad sectors (not sure if this is the right  
> terminology).

What you could do is run a shell from the install CD, then fill the disk
with zeros using 'dd if=/dev/zero of=/dev/<yourdisk> bs=2m'.

As I understand it, modern hard disks cannot be low-level formatted by
the user. It is done at the factory. And bad blocks are re-allocated by
the built-in controller without user intervention. In fact, you'll only
see re-allocated blocks in the smartctl -a output (as
Reallocated_Sector_Ct) when the drive has exhausted its spare
sectors. In which case you'd better replace it, because it is failing.

> I'm starting to get real depressed about this machine... You would  
> think a top-tier data center could keep the power on...

Are you sure that the hardware isn't crapping out on you? At least run
smartctl -a on your disks to see if they failed any self test, and a
monitoring program like mbmon to check on temperatures and voltage
levels.

Roland
-- 
R.F.Smith                                   http://www.xs4all.nl/~rsmith/
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