[ILUG] Hot swap drive?

[Conor Daly]

On Thu, Jul 22, 2004 at 10:23:45AM +0100 or so it is rumoured hereabouts, 
Niall O Broin thought:
> On Thursday 22 July 2004, c.daly at met.ie (Conor Daly) wrote:
> 
> >Can I, while up and running, plug in the disk, do 'mount /dev/hdXX
> >/mnt/point', rsync (or whatever), 'umount /mnt/point', unplug the disk?
> >
> >Or do I have to power off for the plug / unplug stages?
> >
> >In other words, does 'hot swap' mean "you can plug / unplug a mounted drive
> >and all will be fine" or does it mean "you can plug / unplug a drive so long
> >as it's not mounted at the time"?
> 
> Possibly, maybe, who knows. 
> 
> But the real answer has to be no, I'm afraid. You can't really hot plug IDE
> because the system doesn't know the drive is there. When it boots, it doesn't
> find a drive, and then you add one in - how is it to know it's there? If you

OTOH, if the machine boots with the drive installed but not mounted, then
unplug the drive, it (maybe) should be able to mount it later if I plug it
in again.  If not, I can always bounce the machine (for home use...)  If I
want to hotplug in a production environment, I guess a proper caddy is
required.

BTW, will a hard disk get damaged by being plugged / unplugged when not in
use (not mounted, not spinning, not whatever...)?

> correctly requires tri state buffers which you probably WON'T get on a cheap
> caddy from Marx.

No, I presumed not here..
 
> Oh - you certainly CAN'T unplug a mounted drive, no matter what the hardware
> arrangements, without risking massive FS corruption. Always umount first. Kate

Ah, I knew that really...

> A better option might be an external USB-2 (USB is rather slow for a big
> drive) or Firewire drive. If your box doesn't have USB-2 or Firewire, add-in

A number of people at work, using external USB2 hard drives on Suse 8.2
have had problems with FS corruption.  Whether this is a failing drive
problem or an OS or user problem isn't clear.  The other issue is transfer
speeds.
> 
> 
> Niall
> -- 
> Irish Linux Users' Group
> http://www.linux.ie/mailman/listinfo/ilug/
> 

-- 
Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)
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