[CentOS] Removable drive configuration

Robert Heller heller at deepsoft.com
Sun Dec 20 14:27:09 UTC 2009

At Sun, 20 Dec 2009 08:49:02 -0500 CentOS mailing list <centos at centos.org> wrote:

> I have a box running CentOS 5.3 with two Dataport removable drive bays 
> installed on the second IDE interface (/dev/hdc and hdd). I want to 
> configure it so I can plug in and mount various drives at different 
> times, including different size drives. So far it will only recognize 
> the first drive I plug in, and only if I boot the box after inserting 
> the drive.
> Is there any way to set it up so I can mount different size drives 
> freely without having to reboot each time?

PATA (IDE) drives are not hot-swapable -- I don't think either the
kernel IDE driver or many (if any) plain IDE controllers support hot
swapping (probably some IDE *hardware RAID* controllers *might* support
hot swapping).  Most newer SATA controllers, and *some* SCSI
controllers support hot swapping. You are probably better off getting
USB<=>IDE external enclosures if you want 'hot swapable'
functionallity, otherwise you will need to reboot to see the change in
IDE drives.  USB drives are implicitly hot swappable.

Also: to get the second drive to be seen, it would have to be
configured as a slave -- you'll have to set the slave jumper on the
drive itself -- I think that the IDE 'removable' drive carriers don't
jumper the master/slave -- actually they can't, since the IDE interface
does not support drive ID.  SCSI hot swap is handled by the SCA (80
pin, which include power and id) and SATA is one drive one controller
port -- logically one drive one logical controller, with no drive IDs at
all.  (SATA is designed from the ground up to be hot swapable.)

> Thank you,
> Bob McConnell
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos

Robert Heller             -- 978-544-6933
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