Re: Problem with mdadm 3.2.5

[Hans-Peter Jansen <hpj@urpla.net>]

Keep ML cc'ed, please.

On Donnerstag, 28. März 2013 10:31:58 Tarak Anumolu wrote:
> Hi Mr Peter
> Actually we are trying to implement RAID for an embedded device [NVR-Network
> Video Recorder]. For our device we need to have two partitions.
> Its a device structure in our legacy code.
> It's complicated to change into one partition so we are using the existing
> thing in our implementation. 
> We will consider your suggestion to use LVM for making partitions.

Better partition your harddisks beforehand, eg. 

sda1, sda2
sdb1, sdb2
...

and create two mds:

md0: sda1, sdb1
md1: sda2, sdb2

For partitioning, you can do it once, and use sfdisk to copy partition tables 
over, eg.:

fdisk /dev/sda

sfdisk -d /dev/sda | sfdisk /dev/sdb

What others said about the metadata version is still relevant.

Cheers,
Pete

> Thanks for the response
> Tarak
>  
>  
>  
>  
>  
> ------- Original Message -------
> Sender : Hans-Peter Jansen<hpj@urpla.net>
> Date : Mar 28, 2013 18:45 (GMT+09:00)
> Title : Re: Problem with mdadm 3.2.5
>  
> 
> On Donnerstag, 28. März 2013 06:36:03 Tarak Anumolu wrote:
> > Hi
> > 
> > FYI, We followed the below steps and At the end you can see the problem
> > with the file system.
> 
> Tarak, could you do me a flavor, and reread, what I've already written last
> time? Then, attempt to answer the single question below, please.
> 
> > RAID operation on 8 harddisks each of size 1TB with 7 harddisks as raid
> > devices and 1 hard disk as spare device got succeed.
> > 
> > #parted -s /dev/md0 print
> > Model: Linux Software RAID Array (md)
> > Disk /dev/md0: 6001GB
> > Sector size (logical/physical): 512B/512B
> > Partition Table: gpt
> > Number  Start   End     Size    File system  Name     Flags
> >
> >  1      1049kB  60.0GB  60.0GB  xfs          primary
> >  2      60.0GB  6001GB  5941GB  xfs          primary
> >
> > Then We create 2 partitions md0p1 and md0p2.
> > 
> > #cat /proc/partitions
> > major minor  #blocks  name
> >
> >   31        0       8192 mtdblock0
> >   31        1     131072 mtdblock1
> >    8        0  976762584 sda
> >    8        1  976760832 sda1
> >    8       16  976762584 sdb
> >    8       17  976760832 sdb1
> >    8       32  976762584 sdc
> >    8       33  976760832 sdc1
> >    8       48  976762584 sdd
> >    8       49  976760832 sdd1
> >    8       64  976762584 sde
> >    8       65  976760832 sde1
> >    8       80  976762584 sdf
> >    8       81  976760832 sdf1
> >    8       96  976762584 sdg
> >    8       97  976760832 sdg1
> >    8      112  976762584 sdh
> >    8      113  976760832 sdh1
> >    9        0 5860563456 md0
> >  259        0   58604544 md0p1
> >  259        1 5801957376 md0p2
> 
> Why do you insist in creating partitions in an already partitioned device?
> 
> Just do:
> 
> mkfs.xfs /dev/md0
> mount /dev/md0 /mnt
> 
> and be done. It *is* that easy.
> 
> md0p1 and md0p2 are obsolete in this scenario. If you need a more
> complicated setup, check out lvm.
> 
> Pete
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