Re: Adding a disk to a RAID array

Lulani,

You are correct in that the OS sees only 1 drive /dev/sda because the hardware
raid controller card takes care of all the RAID stuff.  I am rung RAID 5
currently with 3 drives, I want to add a 4th, it has been sitting in a cabinet
for when needed.  The drive is then partitioned according to the information I
posted sda1, sda2, etc.  Once I get the new hard drive installed in the BIOS of
the controller card, it will create the /dev/sda seen by the OS as a larger
drive with the end of the drive not being used.  I know that I have to some how
edit fdisk manually so that sda4, the extended partition, ending # shows the new
end of the partition.  I then have to manually edit fdisk again so that the
ending # on sda6 shows the end of the partition and then restore the data.  Like
I said I remember manually doing this once before a long time ago but the Unix
Guru who helped me then is no longer here.  This is something that I will have
to plan downtime for since this is a critical system and I don't want to make to
many mistakes with the changes.

Hope this information clears up any questions.

Elizabeth Martin

LULANI Olsi wrote:

> >From what you are stating it seems that the RAID is implemented in HW. As a
> result the OS does not see anything. All the RAID stuff shows up as single
> drive. The point that you have to back-up all the data in the data partition
> is that the partition during the reconfiguration of the controller will be
> deleted and recreated. Say you have two drives and later it will have three
> drives. The drive will seem the same to OS. The only difference will be the
> space it contains. At this point you will restore all the data from backup
> and the partition will seem to be the same as before but with more free
> space.
>
> Sincerely
> Mr. Olsi Lulani
>
> -----Original Message-----
> From: Elizabeth R Martin [mailto:[email protected]]
> Sent: Friday, March 14, 2003 4:01 PM
> To: Red Hat 7.2
> Subject: Adding a disk to a RAID array
>
> I am not sure where to start so I will just jump right in.  Up until
> last week I had the manual for the SCSI card in my hand and now it has
> managed to disappear.  I am still looking for it, although I have found
> a generic one from Adaptec that I have printed out and will go through.
> Hopefully I will be able to find out what I need to know concerning the
> hardware recognition of a new drive in the array.
>
> Hardware info:
> DPT (bought out by Adaptec) PM2654 I20 BIOS SmartRAID V controller card,
> firmware updated last April
> 3   SCSI Hard drives  36gb Segate
>
> Here's the problem:
>
> I have a SCSI hardware RAID array of 3 drives.  Space is running out on
> the data partition of the array and I need to add another 36gb drive to
> the array. I think that all I need to do for the drive to be seen by the
> hardware is to install the drive and boot up however, I am still looking
> in to that.  Here is the partition information:
>                    start        end     mgb      part type     mounted
> /dev/sda
>    - sda1         1            9        71        ext3            boot
>    - sda2        10         270    2047      Linux-swap
>    - sda3       271        336     518       ext3            tmp
>    - sda4      337        8924   67366    Extended
>        - sda5  337         859    4103      ext3
>        - sda6  860        8924   6324      ext3            data
>
> I want to add the new drive space to the end of sda6 and into the
> mounted data partition but I have not been able to find out any
> information on how to do this.  I have looked through a stack of books,
> asked those in the "know" here at work and no one seems to be able to
> tell me how to do it.  I know that I will have to back every thing up in
> the data partition before doing this.  I also know that I have to do
> something in fdisk.  I once did something like this to a non RAIDed
> Alpha Ultrex system about 6yrs ago but have no idea of how to proceeded
> here.  I am trying not to have to reinstall the entire system just to
> install a new drive.
>
> Assistance is greatly appreciated.
>
> Elizabeth R. E. Martin
> Network Support Specialist
> UT-Houston Medical School
>
> _______________________________________________
> enigma-list mailing list
> [email protected]
> https://listman.redhat.com/mailman/listinfo/enigma-list

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