RAID autodetect fails

Clemente · 01-25-2006, 10:58 AM

Hi all,

my goal is a software RAID, level 1, on two identical SATA Disks.

With:

Quote:

mdadm -Cv /dev/md0 -n2 -l1 /dev/sda1 /dev/sda2

I can create and start the array. I can do mkfs, mount it, everything works fine until rebooting the system.
If done, the array does not run. mdadm --run /dev/md0 brings an error. I can rebuild the array with the command above - not very comfortable.

I guess, that the kernel first searches for an array, and after this, it scans for the SATA drives. Since the array should reside on the SATA drives, it cannot be started.
I post a dmesg snippet with line numbers, that shows the md autodetection before the scsi detection - if I see this correctly.

Does anyone can say me, if I am right or wrong, and, more important, what I can do to get the autodetection working?

Thanks a lot,
Clemens

P.S: All this happens on a debian sarge system, kernel 2.6.8 custom.

Quote:

160:md: linear personality registered as nr 1
161:md: raid0 personality registered as nr 2
162:md: raid1 personality registered as nr 3
163:md: raid5 personality registered as nr 4
164-raid5: automatically using best checksumming function: pIII_sse
165- pIII_sse : 4784.000 MB/sec
166-raid5: using function: pIII_sse (4784.000 MB/sec)
167:md: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27
168-device-mapper: 4.1.0-ioctl (2003-12-10) initialised: dm@uk.sistina.com

(..)

179:md: Autodetecting RAID arrays.228:ata1: SATA max UDMA/133 cmd 0xE900 ctl 0xEA02 bmdma 0xED00 irq 217
180:md: autorun ...
181:md: ... autorun DONE.

(..)

229:ata2: SATA max UDMA/133 cmd 0xEB00 ctl 0xEC02 bmdma 0xED08 irq 217
230-ata1: dev 0 cfg 49:2f00 82:7c6b 83:7f09 84:4673 85:7c69 86:3e01 87:4663 88:007f
231-ata1: dev 0 ATA, max UDMA/133, 398297088 sectors: lba48
232-ata1: dev 0 configured for UDMA/133
233-scsi0 : sata_sis
234-ata2: dev 0 cfg 49:2f00 82:7c6b 83:7f09 84:4673 85:7c69 86:3e01 87:4663 88:007f
235-ata2: dev 0 ATA, max UDMA/133, 398297088 sectors: lba48
236-ata2: dev 0 configured for UDMA/133
237-scsi1 : sata_sis
238- Vendor: ATA Model: Maxtor 6L200M0 Rev: BANC
239- Type: Direct-Access ANSI SCSI revision: 05

Linux.tar.gz · 01-25-2006, 11:08 AM

I don't know software raid, but perhaps:
-raid is compiled as module so the module is loaded after some critical phase.
-you have to specify something to the boot loader.
Hope this helps.

Clemente · 01-25-2006, 11:59 AM

Hi Linux.tar.gz,

thanks for your idea.

I build a custom kernel with
- SCSI
- RAID support, all RAID flavors (1, 2, ...)
compiled direct into the kernel. Without, the autodetection did nothing in dmesg.

I thought about the boot loader, too. I use grub. But I can't think what parameter I should give to the kernel. Google did say nothing, too. At least to me ;-)

I don't really know, where to go. At the moment, I build another kernel with all ata stuff demodulized, build inti the kernel...

Clemens

Clemente · 01-26-2006, 06:02 AM

Finally I got it working.
If someone faces the same prob, perhaps he can use this:
The autodetection system still fails with autodetection :-(

As workaround, I use the /etc/init.d/mdadm-raid script.
I put a symlink into /etc/rcS.d. It was a little difficult to provide correct dependencies between the startup scripts, since the raid script must be run before the mountall script.
The mountall script uses the raid and mounts it into the filesystem. Better the array runs at this moment ;-)
But the raid script needs mountvirtfs and mountprocfs (or so) to be run before...
After two or three dozens of reboots, the system works, now.

Clemente