How-To hotswap a SATA disk ?

[Bingo]

Hi all !

I have a barebone server with 2 sata disks in an hotswap case.
They have been automatically configured by the FC5 installer as a RAID1 array (don't ask me why or how, I don't have a clue, but I just had one disk visible in the partitionning utility, and it was a RAID1 array...).

The question is : how do I use the hotswap feature of my server with FC5 ?
If I just unplug the drive from its bay, how will dmraid react to this ?


Thanks for your help !

[Zipster]

Some info on RAID... RAID1 array can be described as 2 discs mirroring eachother. Thats why you see only one disc. The other one will be a precise copy of the first.

There could also be a RAID0 wich is a Stripeset without parity. This makes the two disks look like one. There is only one problem there. NO redundancy at all! One disc fails and ALL data that is not backuped is gone.

With a mirrored disc it should work something like this. Take out the damaged disc and replace it with a new one. Then the RAID should fix the rest. Remark that it SHOULD do this. I don't know if it DOES this. Read the manual for the RAID-controller (if hardware-RAID) or look for info on the web if there is a software-RAID program.

Hope that this don't mess things up =)

[Bingo]

Hi Zipster, thanks for your reply.
Actually, I know quite well how RAID works.

This is pure software RAID (I disabled all the motherboard's RAID functionnalities), and this why I don't understant how the FC5 controller has chosen to automatically configure them as a RAID1 array.

[worlds6440]

I have a new machine running FC5. I now have a SATA HD caddy which allows three additional SATA hd's to be added.

What I want to know is how to get Linux to use any new SATA HD's I hotswap in?

More Info:
I've tried simply inserting drive. I get a Message in the log files stating "nv_sata: Secondary Device Added". Yet I get no device in "/Dev".

I DO however get the device if I reboot the machine. This is obviously not what I want as I'm trying to set this PC up as a backup device. I want to be able to simply remove and add SATA hard drives willy nilly (obviously not whilst any datas being copied to it!).

If anyones come up against this problem, please let me know.
Foxconn NF4UK8AA Mobo,
AMD 64bit 3200,
IcyDock SATA Backplane,
Seagate Baracuda 250gb SATAII HDs (we have 3 so far)
FC5 64bit

Please, anyone!

[steve941]

you may have to make a new kernel with a custom config
umm, i know there's hotswap support as an option in the kernel config it looks like fedora doesn't have enabled in their kernels ..
or there may be no specific hotswap support for your chipset.
i don't know much about hotswap though -- what it requires support wise in the kernel, umm but look into building your own kernel and check out support options

[worlds6440]

I did a bit of research into enabling SATA Hotswapping int the Kernel as you hinted at and found out that Fedora Core5 has a LibATA module which apparently if the kernel version is less than 2.6.16 wont support Hotswap. I had 2.6.15 64bit installed and am now trying 2.6.17 32bit version. Ill let you know if it works.