I experience the same thing. Two 1 TB drives are set up with two partitions each: one for /boot, one for LVM. Inside the logic volumegroups are separate logic volumes for /, /var, /tmp and swap. Both partitions are mirrored with software RAID (level 1). The other eight 1 TB drives are hooked up to a Dell PERC6/i RAID controller in a hardware array (level 6) with one hotspare. Upon booting the boot loader displays "GRUB loading" for some seconds, then (twice): error: biosdisk read error error: biosdisk read error. Seconds later the systems continues to boot normally. Is there anything more I can investigate to clear up things? Log messages that might reveal something of importance? Cheers > uname -a Linux ***Name*** 2.6.31-14-server #48-Ubuntu SMP Fri Oct 16 15:07:34 UTC 2009 x86_64 GNU/Linux > cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=9.10 DISTRIB_CODENAME=karmic DISTRIB_DESCRIPTION="Ubuntu 9.10" > sudo fdisk -l Platte /dev/sda: 1000.2 GByte, 1000204886016 Byte 255 Köpfe, 63 Sektoren/Spuren, 121601 Zylinder Einheiten = Zylinder von 16065 × 512 = 8225280 Bytes Disk identifier: 0x00078612 Gerät boot. Anfang Ende Blöcke Id System /dev/sda1 * 1 122 979933+ fd Linux raid autodetect /dev/sda2 123 121601 975780067+ 5 Erweiterte /dev/sda5 123 121601 975780036 fd Linux raid autodetect Platte /dev/sdb: 1000.2 GByte, 1000204886016 Byte 255 Köpfe, 63 Sektoren/Spuren, 121601 Zylinder Einheiten = Zylinder von 16065 × 512 = 8225280 Bytes Disk identifier: 0x42424242 Gerät boot. Anfang Ende Blöcke Id System /dev/sdb1 * 1 122 979933+ fd Linux raid autodetect /dev/sdb2 123 121601 975780067+ 5 Erweiterte /dev/sdb5 123 121601 975780036 fd Linux raid autodetect Platte /dev/md1: 999.2 GByte, 999198687232 Byte 2 Köpfe, 4 Sektoren/Spuren, 243944992 Zylinder Einheiten = Zylinder von 8 × 512 = 4096 Bytes Disk identifier: 0x00000000 Festplatte /dev/md1 enthält keine gültige Partitionstabelle Platte /dev/md0: 1003 MByte, 1003356160 Byte 2 Köpfe, 4 Sektoren/Spuren, 244960 Zylinder Einheiten = Zylinder von 8 × 512 = 4096 Bytes Disk identifier: 0x00000000 Festplatte /dev/md0 enthält keine gültige Partitionstabelle WARNING: GPT (GUID Partition Table) detected on '/dev/sdc'! The util fdisk doesn't support GPT. Use GNU Parted. WARNING: The size of this disk is 5.0 TB (4998268190720 bytes). DOS partition table format can not be used on drives for volumes larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID partition table format (GPT). Platte /dev/sdc: 4998.3 GByte, 4998268190720 Byte 255 Köpfe, 63 Sektoren/Spuren, 607671 Zylinder Einheiten = Zylinder von 16065 × 512 = 8225280 Bytes Disk identifier: 0x00000000 Gerät boot. Anfang Ende Blöcke Id System /dev/sdc1 1 267350 2147483647+ ee GPT > sudo mdadm --detail /dev/md0 /dev/md0: Version : 00.90 Creation Time : Fri Nov 20 09:03:34 2009 Raid Level : raid1 Array Size : 979840 (957.04 MiB 1003.36 MB) Used Dev Size : 979840 (957.04 MiB 1003.36 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Fri Nov 20 09:54:55 2009 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 7901eabc:4275a97b:d39e991d:9964d437 Events : 0.20 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 > sudo mdadm --detail /dev/md1 /dev/md0: Version : 00.90 Creation Time : Fri Nov 20 09:03:34 2009 Raid Level : raid1 Array Size : 979840 (957.04 MiB 1003.36 MB) Used Dev Size : 979840 (957.04 MiB 1003.36 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Fri Nov 20 09:54:55 2009 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 7901eabc:4275a97b:d39e991d:9964d437 Events : 0.20 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 > cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdb1[1] sda1[0] 979840 blocks [2/2] [UU] md1 : active raid1 sdb5[1] sda5[0] 975779968 blocks [2/2] [UU] [====>................] resync = 24.9% (243535744/975779968) finish=136.8min speed=89164K/sec unused devices: