quick help needed - smaller disk in raid5?

quick help needed - smaller disk in raid5?

[Hebenstreit Michael]

Hello everybody,

I've been using a Raid5 with 3 disks of exactly the same size, a little bit 
more than 250 GB (reported as 251)

Disk /dev/sdc: 251.0 GB, 251000193024 bytes
255 heads, 63 sectors/track, 30515 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       30513   245095641   fd  Linux raid autodetect

Now I want to add a 4th disk - and got one slightly smaller:

sanjose:~ # fdisk -l /dev/sdd
Disk /dev/sdd: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdd doesn't contain a valid partition table



Is it nevertheless possible (with some minimal losses in possible size) to add 
the new disk? The Funny thing - all disks are from Maxtor, and should have 
the same size.

Thanks a lot

Michael


-- 
Michael HEBENSTREIT
FH JOANNEUM / Aviation
Alte Poststr. 149, 8020 Graz, Austria
Tel.: +43-316-5453-6421
Fax.: +43-316-5453-6401
e-mail: michael.hebenstreit@fh-joanneum.at

Re: quick help needed - smaller disk in raid5?

[Tim Moore]

'fdisk -lu' shows in sectors of 512 bytes, useful in matching partition 
sizes for slightly different disks.

You will have to resize to the smallest (30401 cylinders).

Hebenstreit Michael wrote:
> Hello everybody,
> 
> I've been using a Raid5 with 3 disks of exactly the same size, a little bit 
> more than 250 GB (reported as 251)
> 
> Disk /dev/sdc: 251.0 GB, 251000193024 bytes
> 255 heads, 63 sectors/track, 30515 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1               1       30513   245095641   fd  Linux raid autodetect
> 
> Now I want to add a 4th disk - and got one slightly smaller:
> 
> sanjose:~ # fdisk -l /dev/sdd
> Disk /dev/sdd: 250.0 GB, 250059350016 bytes
> 255 heads, 63 sectors/track, 30401 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> 
> Disk /dev/sdd doesn't contain a valid partition table
> 
> 
> 
> Is it nevertheless possible (with some minimal losses in possible size) to add 
> the new disk? The Funny thing - all disks are from Maxtor, and should have 
> the same size.
> 
> Thanks a lot
> 
> Michael
> 
> 

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