[CentOS] Re: Cannot re-make a software raid pair

[Scott Silva]

Nigel Kendrick spake the following on 10/5/2006 3:48 PM:
>  
> 
> -----Original Message-----
> From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On Behalf
> Of Scott Silva
> Sent: Thursday, October 05, 2006 11:15 PM
> To: centos at centos.org
> Subject: [CentOS] Re: Cannot re-make a software raid pair
> 
> Nigel Kendrick spake the following on 10/5/2006 12:45 PM:
>> Apologies if you get this twice - the first one didn't seem to make it... 
>>
>> Hi Guys,
>>
>> I have just replaced a faulty Max...woah, wait...this one's a 
>> Seagate... IDE hard disk but I cannot remake the software raid pair.
>>
>> The currently running disk is hda and I am trying to add back hdg - 
>> both are master drives on separate controllers.
>>
>> I have run fdisk on hdg and created the same partition structure as 
>> had and changed their types to 'fd' but when I try and rebuild the array I
> get:
>> mdadm /dev/md0 -a /dev/hdg1
>>
>> mdadm: hot add failed for /dev/hdg1: Invalid argument
>>
>> If I look at /var/log/messages, I have:
>>
>> Oct  5 16:04:39 petdoctors kernel: md: could not bd_claim hdg1.
>> Oct  5 16:04:39 petdoctors kernel: md: error, md_import_device() 
>> returned
>> -16
>>
>> >From other postings, this seems to imply the hdg1 partition is mounted 
>>> but I
>> can find no evidence of this (df or cat /proc/mounts or lsof). I have 
>> done sone googling and found others having fun with this but no 
>> specific solution.
>>
>> Anyone?
> Maybe the table didn't get re-read after fdisk was done. I usually use
> sfdisk just because I can copy a partition table without making my usual
> fat-fingered typos. Are you sure that the new drive isn't smaller than the
> old? Even by a few cylinders.
> 
> -- 
> 
> Hi Scott,
> 
> Disks are 100% identical - right down to the last cylinder...hda is the live
> disk and hdg is the new one...
> 
> [root at petdoctors ~]# sfdisk --no-reread /dev/hda
> 
> Disk /dev/hda: 24321 cylinders, 255 heads, 63 sectors/track
> Old situation:
> Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
> 
>    Device Boot Start     End   #cyls    #blocks   Id  System
> /dev/hda1   *      0+     12      13-    104391   fd  Linux raid autodetect
> /dev/hda2         13     273     261    2096482+  82  Linux swap
> /dev/hda3        274   24320   24047  193157527+  fd  Linux raid autodetect
> /dev/hda4          0       -       0          0    0  Empty
> Input in the following format; absent fields get a default value.
> <start> <size> <type [E,S,L,X,hex]> <bootable [-,*]> <c,h,s> <c,h,s>
> Usually you only need to specify <start> and <size> (and perhaps <type>).
> 
> /dev/hda1 :
> [root at petdoctors ~]# sfdisk /dev/hdg            
> Checking that no-one is using this disk right now ...
> OK
> 
> Disk /dev/hdg: 24321 cylinders, 255 heads, 63 sectors/track
> Old situation:
> Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
> 
>    Device Boot Start     End   #cyls    #blocks   Id  System
> /dev/hdg1          0+     12      13-    104391   fd  Linux raid autodetect
> /dev/hdg2         13     273     261    2096482+  82  Linux swap
> /dev/hdg3        274   24320   24047  193157527+  fd  Linux raid autodetect
> /dev/hdg4          0       -       0          0    0  Empty
> Input in the following format; absent fields get a default value.
> <start> <size> <type [E,S,L,X,hex]> <bootable [-,*]> <c,h,s> <c,h,s>
> Usually you only need to specify <start> and <size> (and perhaps <type>).
> 
> /dev/hdg1 :
> 
> [root at petdoctors ~]# mdadm /dev/md1 -a /dev/hdg3
> mdadm: hot add failed for /dev/hdg3: Invalid argument
> [root at petdoctors ~]# 

I know this is a real basic question, but did you fail then remove the old
drive first?


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