The old raid on the CentOS server cannot be formatted.

The old raid on the CentOS server cannot be formatted.

An old hard disk is attached to the server. If you want to format the historical data and save it, use fdisk to report the following error:

/Dev/sda1 isapparently in use by the system; will not make a filesystem here!

In general, this is because the disk has been used by the system or mounted to another place. Use mount and df-lh to confirm that the disk is not used.

I have compiled a similar article in my previous blog:

/Dev/sdxx isapparently in use by the system; will not make a filesystem here! Solution

Http://blog.csdn.net/tianlesoftware/article/details/8594958

In this article, a shared device is mounted to the same two different nodes, but here I am mounting a device to a server, so the situation is different from what we did before.

Google said that it was affected by the RAID information left on the previous disk. The system will automatically discover raid based on the residual information. Due to the automatic identification of the system, the hard disk is virtualized into a raid (even if there is no real raid), which indicates that the disk is in use and cannot be formatted.

Confirm:

[Root @ web1 ~] # Dmraid-s

ERROR: ddf1: wrong # of devices in RAID set "ddf1_40da-5a8680b02520202020202020209a33c30a354a45" [1/2] on/dev/sda

* ** Group superset. ddf1_disks

--> * Inconsistent * Active Subset

Name: ddf0000403475a8680b02520202020202020209a33c30a3a354a45

Size: 145051648

Stride: 128

Type: mirror

Status: inconsistent

Subsets: 0

Devs: 1

Spares: 0

[Root @ web1 mapper] # dmsetup status

Ddf0000404255a8680b025202020202020209a33c30a354a45: 0 145051651 linear

You can use the following method to release a disk:

1) dmsetup remove_all

[Root @ web1 mapper] # dmsetup remove_all

# Dmsetup remove/dev/mapper/[device]

[Root @ web1 mapper] # dmsetup status

No devices found

2) use dmraid to disableactive: dmraid-a no

[Root @ web1 conf] # dmraid-a no

ERROR: ddf1: wrong # of devices in RAID set "ddf1_40da-5a8680b02520202020202020209a33c30a354a45" [1/2] on/dev/sda

ERROR: device "ddf0000403475a8680b02520202020202020209a33c30a3a354a45" cocould not befound

RAID set "ddf1_40da-5a8680b02520202020202020209a33c30a3a354a45" is not active

[Root @ web1 conf] #

-- Verification:

[Root @ web1 ~] # Dmraid-s

ERROR: ddf1: wrong # of devices in RAID set "ddf1_40da-5a8680b02520202020202020209a33c30a354a45" [1/2] on/dev/sda

* ** Group superset. ddf1_disks

--> * Inconsistent * Subset

Name: ddf0000403475a8680b02520202020202020209a33c30a3a354a45

Size: 145051648

Stride: 128

Type: mirror

Status: inconsistent

Subsets: 0

Devs: 1

Spares: 0

[Root @ web1 ~] #

After the disk is released, the disk can be formatted and mounted.

However, after the system is restarted, the disk RAID information will still be identified and the disk cannot be mounted normally. Try to clear the RAID information on the disk.

-- Use dmraid-x:

[Root @ web1 ~] # Dmraid-x

ERROR: ddf1: wrong # of devices in RAID set "ddf1_40da-5a8680b02520202020202020209a33c30a354a45" [1/2] on/dev/sda

About to delete RAID setddf0000403475a8680b025202020202020209a33c30a354a45

WARNING: The metadata stored on theraidset (s) will not be accessible after deletion

Do you want to continue? [Y/n]: y

ERROR: Raid set deletion is notsupported in "ddf1" format

[Root @ web1 ~] #

-- Use: dmraid-rE

[Root @ web1 mapper] # dmraid-rE

Do you really want to erase "ddf1" ondisk metadata on/dev/sda? [Y/n]: y

ERROR: ddf1. seeking device "/dev/sda" to 38070153641984

ERROR: writing metadata to/dev/sda, offset74355768832 sectors, size 0 bytes returned 0

ERROR: erasing ondisk metadata on/dev/sda

[Root @ web1 mapper] #

Cannot be cleared successfully, so that even if I add the mount information to/etc/fstab, the mount will not work after the startup. So we chose a method.

The following information is added to the/etc/rc. d/rc. local file:

Dmraid-a no

Sleep 5

Mount/dev/sda1/backup

In this way, automatic mounting is enabled.