[Gllug] RAID level 1

[Rich Walker]

wendy carr <wendy_carr2003 at yahoo.co.uk> writes:

> Hi,
> Thanks for the tips.I dont seem to have /etc/raidtab
> and output of cat /proc/mdstat is
>
> root at RAID etc]# cat /proc/mdstat
> Personalities : [raid1]
> read_ahead not set
> unused devices: <none>

There are no raid devices here!

It should look more like:

Personalities : [linear] [raid0] [raid1] [raid5] [multipath] 
read_ahead 1024 sectors
md1 : active raid5 hdd1[2] hdg1[0] hdf1[1] hdb2[3]
      359292672 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]
      
md0 : active raid1 hdg2[0] hde1[1]
      19583168 blocks [2/2] [UU]
      
unused devices: <none>

where md0 is the raid-1.

Using mdadm, I can do:

thoth:/# mdadm --misc --detail /dev/md0
/dev/md0:
        Version : 00.90.00
  Creation Time : Mon Jan  6 06:07:44 2003
     Raid Level : raid1
     Array Size : 19583168 (18.68 GiB 20.05 GB)
    Device Size : 19583168 (18.68 GiB 20.05 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Fri Feb 13 13:54:26 2004
          State : dirty, no-errors
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 1


    Number   Major   Minor   RaidDevice State
       0      34        2        1      active sync   /dev/hdg2
       1      33        1        0      active sync   /dev/hde1
           UUID : a061d4aa:672bcb2d:bcfe98f7:ddaf2c70
         Events : 0.275
thoth:/# 


If I wanted to assemble a raid-1 array from 2 partitions I had already
created and set to type fd, I would do:

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/hde1 /dev/hdg2

This will create and initialise the array.

You should then see it when you do "cat /proc/mdstat"


hope this helps
cheers, Rich.


> [root at RAID etc]#
>
> So i think at last i am running on RAID 1.In case of a
> disk failure will be able to plug in a similar disk
> and re-mirror the existing hard drive.if so how do i
> do that ?I checked that raidtools 1.000 is installed 
> is that the best tools for software RAID?.



>
> Thanks again.
>
>
> 	
> 	
> 		
> ___________________________________________________________
> Yahoo! Messenger - Communicate instantly..."Ping" 
> your friends today! Download Messenger Now 
> http://uk.messenger.yahoo.com/download/index.html
> -- 
> Gllug mailing list  -  Gllug at gllug.org.uk
> http://lists.gllug.org.uk/mailman/listinfo/gllug

-- 
rich walker         |  Shadow Robot Company | rw at shadow.org.uk
technical director     251 Liverpool Road   |
need a Hand?           London  N1 1LX       | +UK 20 7700 2487
www.shadow.org.uk/products/newhand.shtml
-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug