Hi,

I am new to Linux and trying to configure RAID1 on CentOS 5.2. The configuration is successful and I am able to boot the machine by replacing any of the drive after making some changes in GRUB for the next drive.

But it seems my disks are not syncing together. I don't have any clue. Please help me to understand this.

Thanks in advance!

kartik

First look to /proc/mdstat.

Hi,

I looked at the result it gives me following details;

# cat /proc/mdstat

Personalities : [raid1]
md0 : active raid1 hda1[0]
200704 blocks [2/1] [U_]

md1 : active raid1 hda2[0]
488183104 blocks [2/1] [U_]

unused devices: <none>

I am not able to understand on how to sync both the drive.

Please help me.

Best regards,

Ranjeet Rai

fdisk -l by root

Hi,

I setup RAID again, and found that my both the drive is syncing by running the command #cat /proc/mdstat. The status was showing that it is syncing. I left them syncing and made some changes like installing application and copying data in home folder and on desktop.

Once the resync was complete, I removed slave drive and it booted from the master drive and I was able to found all the changes. Then I removed the master drive and added the previously removed drive. Although, it stop at GRUB> but after making changes in GRUB it started booting and I found all the changes as it is. This shows that initially the RAID was successfully configured.

Now I have added both the drive, I am making some changes to it like copying some other file in home directory and checking on both the drive for it's availability, but it shows on one only.

I checked it's status by running following command;

The output from;

# cat /proc/mdstat

Personalities : [raid1]
md1 : active raid1 hdb2[1] hda2[0]
4096448 blocks [2/2] [UU]

md0 : active raid1 hda1[0]
10241280 blocks [2/1] [U_]

unused devices: <none>

Then;


# fdisk -l

Disk /dev/hda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 1275 10241406 fd Linux raid autodetect
/dev/hda2 1276 1785 4096575 fd Linux raid autodetect

Disk /dev/hdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hdb1 * 1 1275 10241406 fd Linux raid autodetect
/dev/hdb2 1276 1785 4096575 fd Linux raid autodetect

Disk /dev/md0: 10.4 GB, 10487070720 bytes
2 heads, 4 sectors/track, 2560320 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md0 doesn't contain a valid partition table

Disk /dev/md1: 4194 MB, 4194762752 bytes
2 heads, 4 sectors/track, 1024112 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md1 doesn't contain a valid partition table


Then,

]# mdadm --detail /dev/md0
/dev/md0:
Version : 00.90.03
Creation Time : Thu Dec 11 11:28:45 2008
Raid Level : raid1
Array Size : 10241280 (9.77 GiB 10.49 GB)
Used Dev Size : 10241280 (9.77 GiB 10.49 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Thu Dec 11 18:56:56 2008
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

UUID : 65363e94:f26f3493:2876b70b:af9364ff
Events : 0.1142

Number Major Minor RaidDevice State
0 3 1 0 active sync /dev/hda1
1 0 0 1 removed


and Then;

# mdadm --detail /dev/md1
/dev/md1:
Version : 00.90.03
Creation Time : Thu Dec 11 11:28:43 2008
Raid Level : raid1
Array Size : 4096448 (3.91 GiB 4.19 GB)
Used Dev Size : 4096448 (3.91 GiB 4.19 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1
Persistence : Superblock is persistent

Update Time : Thu Dec 11 13:04:49 2008
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0

UUID : e091d7e6:31b1c02c:81370c2f:32087bb4
Events : 0.4

Number Major Minor RaidDevice State
0 3 2 0 active sync /dev/hda2
1 3 66 1 active sync /dev/hdb2

Please, help me to resync both the drive.

Regards,

Kartikrajus