[clug] hot-swap (hotplug) sata, Intel ICH7 controller

[Steve Granger]

Hi,

I'm currently testing the capabilities of a SATA hotswap system and
whether it is possible to replace a failed disk without powering down
the machine. So far I have been unsuccessful and would be interested in
others experiences with similar hardware.

Should I try and use the proprietary adaptec driver?  or dmraid? maybe
my controller just can't hot plug devices?

--
Steve

= Background =

It's running the latest ubuntu server, 7.04. I've already had some
problems booting software RAID
https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/75681
but am using this work around
http://ubuntuforums.org/showpost.php?p=2236181&postcount=5


The box is a Supermicro SuperServer 5015M-T/T+ 1RU with supposed SATA
RAID hotswap capabilities. Two segate 500 GB ES drives.
http://www.supermicro.com/products/system/1U/5015/SYS-5015M-T.cfm


lspci -vv gives this information about the SATA controller

00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family)
Serial ATA Storage Controller IDE (rev 01) (prog-if 8f [Master SecP SecO
PriP PriO])
        Subsystem: Super Micro Computer Inc Unknown device 7980
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin B routed to IRQ 19
        Region 0: I/O ports at 30e8 [size=8]
        Region 1: I/O ports at 30dc [size=4]
        Region 2: I/O ports at 30e0 [size=8]
        Region 3: I/O ports at 30d8 [size=4]
        Region 4: I/O ports at 30b0 [size=16]
        Region 5: Memory at e0000400 (32-bit, non-prefetchable) [size=1K]
        Capabilities: [70] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA
PME(D0-,D1-,D2-,D3hot+,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-


It's a fakeraid controller.
http://linuxmafia.com/faq/Hardware/sata.html
and adaptec provides a propritery driver for it
ftp://ftp.supermicro.com/driver/Diskimag/Adaptec/ICH7R/
though I've decided not to go down this path yet and it maybe a bit
tricky getting it to work with an ubuntu kernel.


I haven't tried to use dmraid to see the fake raid device, I'm thinking
software raid will be easier and more reliable. I could be wrong?

The libata sata website
http://linux-ata.org/driver-status.html#ich5
mentions that this controller does not support hotplug using ata_pxii
but may using the ahci
http://linux-ata.org/driver-status.html#ahci
ubuntu installed and loaded the ata_pxii module, I'll trying putting the
ahci first in
/etc/initramfs-tools/modules

hotplug may work with this card
http://linux-ata.org/software-status.html#hotplug

I'm getting the results that are commonly associated with a sata
controller not supporting hotplug i.e. when I yank the drive the system
hangs as it recognises the removal of the drive as an ata failure. Once
the drive is returned it becomes responsive. Didn't get to check the
state of the md devices as I thought the machine had hung and issued a
reboot (3 finger salute).

I've shut the machine down and removed a drive, started it back up in a
degraded state okay, put the drive back in ... and received no response
from Linux, nothing at all from dmesg. Did a udevtrigger, nothing.
Rebooted, the drive was seen and after manually telling mdadm to
assemble with the returned drive, got the md devices to resync.

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