RAID1 removal

RAID1 removal

[Norman Zhang]

Hi,

I tried to remove a hot-swap RAID1 SCSI disk from the chassis. So I issued
the following command

> raidsetfaulty /dev/md4 /dev/sdd6
> raidhotremove /dev/md4 /dev/sdd6

But got the following message,

/dev/md4: cannot hot-remove disk: disk is not in array!

So I presume the disk is offline or something, and issued the following
command

echo "scsi remove-single-device 1 0 3 0" > /proc/scsi/scsi

When I checked the newly created /proc/scsi/scsi, the device is still listed
in the file. I checked /proc/mdstat and saw the following

md4: active raid1 scsi/host1/bus0/target2/lun0/part6[0]
     521984 blocks [2/1][U_]

How do I remove the device, so I can add a new device to reconstruct the
array again? Please give me a few pointers?

Regards,
Norman

Re: RAID1 removal

[Norman Zhang]

system_lists@nullzone.org wrote:

> You just need change the disk now and use the 'hotadd' tool to
> insert the new one into the raid. I think could be great
> update the file /etc/raidtab too.

So I don't need to remove drive from /proc/scsi/scsi?

> About you are looking in /proc/mdstat ... you see only a disk on a 2
> disk raid. Where is the second one? out ... u got that using the
> setfaulty...

The faulty disk is still in the chassis. I pull the disk out by accident and
stuck it back in afterwards 8( But I did set raidsetfaulty after that as
described below.

Regards,
Norman

>> I tried to remove a hot-swap RAID1 SCSI disk from the chassis. So I
>> issued the following command
>>
>>> raidsetfaulty /dev/md4 /dev/sdd6
>>> raidhotremove /dev/md4 /dev/sdd6
>>
>> But got the following message,
>>
>> /dev/md4: cannot hot-remove disk: disk is not in array!
>>
>> So I presume the disk is offline or something, and issued the
>> following command
>>
>> echo "scsi remove-single-device 1 0 3 0" > /proc/scsi/scsi
>>
>> When I checked the newly created /proc/scsi/scsi, the device is
>> still listed in the file. I checked /proc/mdstat and saw the
>> following
>>
>> md4: active raid1 scsi/host1/bus0/target2/lun0/part6[0]
>>      521984 blocks [2/1][U_]
>>
>> How do I remove the device, so I can add a new device to reconstruct
>> the array again? Please give me a few pointers?

Re: RAID1 removal

[Norman Zhang]

> system_lists wrote:
>
> Well, u have got that disk out of the Raid so its not in use.
>
> So you must (I THINK BUT I HAVENT DONE ANYTIME ... when I have
> needed to upgrade a Raid I have always programed a shutdown
> in the server):
>
> 1- remove the drive
> 2- remove the drive from the proc (from the kernel)
> 3- add a new drive
> 4- add a new drive in proc (in the kernel)
> 5- do some checks ...
> 6- add the drive into the Raid with 'raidhotadd'

Thanks. I just did a raidhotadd the drives are now back in sync. I see the
drive is in the array again.

Regards,
Norman