CentOS - Apr 2013 - Formatting a USB Drive

Hi All,

I have a Drobo, connected to a CentOS 6.4 box. The box sees it as /dev/sdg.

I want to format it ext3 (as they dont support ext4) but when I try I get:

# fdisk -u /dev/sdg

WARNING: GPT (GUID Partition Table) detected on '/dev/sdg'! The util
fdisk
doesn't support GPT. Use GNU Parted.


WARNING: The size of this disk is 17.6 TB (17592186044416 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and
GUID
partition table format (GPT).


WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c').

So I run:
# parted
GNU Parted 2.1
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) select /dev/sdg
Using /dev/sdg
(parted) print
Model: DROBO DroboPro (scsi)
Disk /dev/sdg: 17.6TB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start  End  Size  File system  Name  Flags

(parted)

and looking at an example of creating a partition: (parted) mkpart primary
106 16179

I dont know what to do next since I dont see any partitions listed. I dont
know what do to for the start and end point, although the man page says
"size in MB". Do I just say 0 to (and convert 16.0TB to MB? Yes, I
know it
says 17.6 TB but this model drobo can only support partitions up to 16tb
without making a second partition.

Can anyone provide some advice on that I am missing conceptually?

Jason

On Wed, Apr 10, 2013 at 11:54 AM, Jason T. Slack-Moehrle
<slackmoehrle at gmail.com> wrote:
>
> I have a Drobo, connected to a CentOS 6.4 box. The box sees it as /dev/sdg.
>
> # parted
> GNU Parted 2.1
> Using /dev/sda
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) select /dev/sdg
> Using /dev/sdg
> (parted) print
> Model: DROBO DroboPro (scsi)
> Disk /dev/sdg: 17.6TB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number  Start  End  Size  File system  Name  Flags
>
> (parted)
>
> and looking at an example of creating a partition: (parted) mkpart primary
> 106 16179
>
> I dont know what to do next since I dont see any partitions listed. I dont
> know what do to for the start and end point, although the man page says
> "size in MB". Do I just say 0 to (and convert 16.0TB to MB? Yes,
I know it
> says 17.6 TB but this model drobo can only support partitions up to 16tb
> without making a second partition.
>
> Can anyone provide some advice on that I am missing conceptually?
If you have a GUI desktop installed you can install the gparted
package from EPEL. It is easier to use than raw parted and mkfs.

--
  Les Mikesell
     lesmikesell at gmail.com

Jason T. Slack-Moehrle wrote:
>
> I have a Drobo, connected to a CentOS 6.4 box. The box sees it as
> /dev/sdg.
>
> I want to format it ext3 (as they dont support ext4) but when I try I get:
<snip>
> So I run:
> # parted
> GNU Parted 2.1
> Using /dev/sda
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) select /dev/sdg
> Using /dev/sdg
> (parted) print
> Model: DROBO DroboPro (scsi)
> Disk /dev/sdg: 17.6TB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number  Start  End  Size  File system  Name  Flags
>
> (parted)
>
> and looking at an example of creating a partition: (parted) mkpart primary
> 106 16179
>
> I dont know what to do next since I dont see any partitions listed. I dont
> know what do to for the start and end point, although the man page says
> "size in MB". Do I just say 0 to (and convert 16.0TB to MB? Yes,
I know it
> says 17.6 TB but this model drobo can only support partitions up to 16tb
> without making a second partition.
>
> Can anyone provide some advice on that I am missing conceptually?
Several issues. First, if you use 4k blocks, the max filesystem size for
ext3 is 16TB (see wikipedia on ext3). Second, I can't remember where, but
on some filesystem tool's manpage, I read that the tools have problems
going over 16TB. Third, fsck on a 16TB filesystem will take *days*,
literally. I'm setting up, right now, a humongous RAID box, and I'll
probably be divvying up the 42TB (mirrored!) as 3 14TB filesystems, and
they're going to be ext4.

        mark

On 4/10/2013 9:54 AM, Jason T. Slack-Moehrle wrote:
> # parted
> GNU Parted 2.1
here's my parted recipe for making very large volumes...   this will 
fill the disk, reserving 512K up front to be on a reasonable stripe boundary

|parted /dev/sdb ||"mklabel gpt"|
|parted -a none /dev/sdb ||"mkpart primary 1024s -1s"|

I would under NO conditions make a EXT3 volume anywheres NEAR as big as 
you're talking about.   my preference for large volumes is XFS.

     VG=vg_$(hostname -s)_data
     vgcreate $VG /dev/sdb1
     lvcreate --size 8T --name lv_data $VG
     mkfs.xfs  /dev/$VG/lv_data
     mount /dev/$VG/lv_data /data

if your storage device presents the storage as a block device, then 
there's no 'support' issues I'm aware of for file systems, its
just
sectors as far as the storage device is concerned, the file system is 
strictly up to your OS.


-- 
john r pierce                                      37N 122W
somewhere on the middle of the left coast

From: Jason T. Slack-Moehrle <slackmoehrle at
gmail.com>
> So I run:
> # parted
> GNU Parted 2.1
> Using /dev/sda
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) select /dev/sdg
> Using /dev/sdg
> (parted) print
> Model: DROBO DroboPro (scsi)
> Disk /dev/sdg: 17.6TB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number? Start? End? Size? File system? Name? Flags
>
> (parted)
>
> and looking at an example of creating a partition: (parted) mkpart primary
> 106 16179
>
> I dont know what to do next since I dont see any partitions listed. I dont
> know what do to for the start and end point, although the man page says
> "size in MB". Do I just say 0 to (and convert 16.0TB to MB? Yes,
I
> know it
> says 17.6 TB but this model drobo can only support partitions up to 16tb
> without making a second partition.
>
> Can anyone provide some advice on that I am missing conceptually?
When I had to play with GPT for a 3TB disk, I did:
? gdisk -l /dev/sdc
? parted -s /dev/sdc mklabel gpt
? parted -s -a optimal /dev/sdc unit s mkpart primary ext4 2048 <MAXVALUE>

Not sure if optimal, but it worked...

JD