Hi William You're right ... I do have 2 HDs and my root is not what I thought it is! Here is what is happening with this system: It has a SIL SATA RAID0/1 card installed with 2x 160GB SATA HDs connected to it. The card is configured to mirror between the HDs (RAID1). But as I saw now Linux actually sees both HDs twice as dmesg shows: SCSI subsystem initialized libata version 3.00 loaded. sata_sil 0000:06:00.0: version 2.3 ACPI: PCI Interrupt 0000:06:00.0[A] -> GSI 21 (level, low) -> IRQ 66 scsi0 : sata_sil scsi1 : sata_sil ata1: SATA max UDMA/100 mmio m512 at 0xe0004800 tf 0xe0004880 irq 66 ata2: SATA max UDMA/100 mmio m512 at 0xe0004800 tf 0xe00048c0 irq 66 ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310) ata1.00: ATA-7: WDC WD1600AAJS-00PSA0, 05.06H05, max UDMA/133 ata1.00: 312581808 sectors, multi 16: LBA48 NCQ (depth 0/32) ata1.00: configured for UDMA/100 ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 310) ata2.00: ATA-7: WDC WD1600AAJS-00PSA0, 05.06H05, max UDMA/133 ata2.00: 312581808 sectors, multi 16: LBA48 NCQ (depth 0/32) ata2.00: configured for UDMA/100 Vendor: ATA Model: WDC WD1600AAJS-0 Rev: 05.0 Type: Direct-Access ANSI SCSI revision: 05 SCSI device sda: 312581808 512-byte hdwr sectors (160042 MB) sda: Write Protect is off sda: Mode Sense: 00 3a 00 00 SCSI device sda: drive cache: write back SCSI device sda: 312581808 512-byte hdwr sectors (160042 MB) sda: Write Protect is off sda: Mode Sense: 00 3a 00 00 SCSI device sda: drive cache: write back sda: sda1 sda2 sda3 sda4 sd 0:0:0:0: Attached scsi disk sda Vendor: ATA Model: WDC WD1600AAJS-0 Rev: 05.0 Type: Direct-Access ANSI SCSI revision: 05 SCSI device sdb: 312581808 512-byte hdwr sectors (160042 MB) sdb: Write Protect is off sdb: Mode Sense: 00 3a 00 00 SCSI device sdb: drive cache: write back SCSI device sdb: 312581808 512-byte hdwr sectors (160042 MB) sdb: Write Protect is off sdb: Mode Sense: 00 3a 00 00 SCSI device sdb: drive cache: write back sdb: sdb1 sdb2 sdb3 sdb4 sd 1:0:0:0: Attached scsi disk sdb /etc/fstab looks for root on /dev/sdb1, while grub looks (and finds) it's configuration (hd0,0) which corresponds to sda1. The thing that strikes me is that the mirror works for grub (as it only sees 1 HD), but doesn't work for Linux. This defeats the purpose of having a RAID1 to begin with :-( Unlike your scenario this system was installed from scratch (CentOS is the only install) and it was done after the mirror was setup in SIL card bios. BTW: the SIL card boot messages claims that the mirror set is valid and active. I will hace to check into this. -- TIA Paolo -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20090203/d35ebd0c/attachment-0005.html>