[CentOS] Hot swap SATA?

Wed Aug 22 03:31:30 UTC 2007
Feizhou <feizhou at graffiti.net>

Lamar Owen wrote:
> On Tuesday 21 August 2007, Feizhou wrote:
>> Les Mikesell wrote:
>>> Jim Perrin wrote:
>>>>> Should it be possible to hot-swap SATA drives with Centos5? 
> 
>>>> Depends on the SATA controller, but yes. If the controller allows, you
>>>> can hotswap sata drives.
> 
>>> How are the names supposed to work when one may be missing at bootup and
>>> added later?
> 
>> I thought the system would just assign the next available /dev/sdx?
> 
>> Then there was the post about wanting to be able to pull a SATA/eSATA
>> disk in and have the system automatically mount whatever filesystem is
>> on the disk...
> 
> That was mine.  Still working on it.

Would it have to smarts to live partition type FD alone?

> 
> As to the hardware support, the definitive answer is found at 
> www.linux-ata.org  
> 
> As to device naming, use LABEL= to fix that.  SCSI device naming on Linux 
> stinks.  

Oh yeah!

> 
> I'm dinking around with a Ubuntu install right now that is giving me fits 
> because of linux PCI/SCSI weirdness.  The boot drive (as set in the BIOS) is 
> probed by the kernel as /dev/sdc.  Fun.  The setup has two 80GB drives in MD 
> RAID1 (200MB /boot on /dev/md0, and 77GB / on /dev/md1, both on the same 
> drives) and four 250GB drives in 3-disk RAID5 with a hotspare.  The drives 
> are spread on three two port controllers (no, I don't have a four or six port 
> controller handy, not an option in this case).  Still working grub to get the 
> thing to boot.... 

Ugh...

> 
> LABEL= does actually have its uses; I migrated a filesystem on a CentOS 4 VM 
> running on one of our two VMware ESX beasts (2x Dell 6950, 4x dual core 
> Opterons, 32GB RAM each, dual 4Gb/s fibre-channel to 2x EMC CLARiiON 
> CX3-10c's with 20TB each) from the internal 3x300GB RAID to a 1.95TB LUN on 
> the CX3.  By using LABEL=, I was able to blow the drive away in VI Client on 
> the VM, and boot right up without device ordering problems.

:-)

> 
> But I have also been bitten by the 'LABELs are the same on cloned disks' fun 
> and games....
> 
> What I'm currently doing with the eSATA deal is having an entry in fstab, set 
> to noauto, and using LABEL=, and an icon in KDE to mount it on the desktop.  
> it is not seamless; unmounting is much more of a chore, as KDE has fun with 
> the icon, doesn't enable the context menu 'safely remove' (aka, unmount) 
> option, etc.  But it's better than nothing.  Just haven't had time to see how 
> to enable SCSI removable support (dig through the udev and hotplug stuff 
> sometime and you'll see what I mean) in libata as yet.  With SCSI removable 
> support (which usbstorage implements, which is why it works) the system Just 
> Works properly.

Maybe when I get a box to play with....the OpenSolaris box is already in 
production so I cannot experiment there.