RAID – MDADM does not create an array greater than 10TB

By Storage

>I have a server with 6 4TB drives running Ubuntu 14.04 LTS.
>One of the drives is for the system/OS
>I want to use the other 5 Two drives are as close as possible to 20TB of storage space
>This is a short-term data analysis project, so RAID 0 is good
>I used fdisk to create a ~4TB partition on each of the 5 drives

< /p>

After running mdadm to create a RAID 0 array, the result is only a 10TB device on /dev/md0. Half the size I expected!

This is the command I used to create the array:

mdadm --create --verbose /dev/md0 --level=stripe --raid -devices=5 /dev/sd[bcdef]1

The following is the output of fdisk -l. Any ideas on why I can’t get more space from the drive? 

Disk /dev/sda: 4000.8 GB, 4000787030016 bytes
255 heads, 63 sectors/track, 486401 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sda1 1 4294967295 2147483647+ ee GPT

Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes< br />90 heads, 3 sectors/track, 28940878 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xda4f04e2

Device Boot Start End Blocks Id System
/dev/sdb1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sdc: 4000.8 GB, 4000787030016 bytes
25 he ads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/ O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc9e57616

Device Boot Start End Blocks Id System
/dev/sdc1 2048 4294967294 2147482623+ 83 Linux 

Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x53bed1ab
< br />Device Boot Start End Blocks Id System
/dev/sdd1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sde: 4000.8 GB, 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xbc5c1069

Device Boot Start End Blocks Id System
/dev/sde1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sdf: 4000.8 GB , 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4801480c

Device Boot Start End Blocks Id System
/dev /sdf1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/md0: 10995.1 GB, 10995108413440 bytes
2 heads, 4 sectors/track, -1610614656 cylinders, total 21474821120 sectors
 Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/ph ysical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 2621440 bytes
Disk identifier: 0x00000000

Disk /dev/md0 doesn' t contain a valid partition table

delete 1 from the end of the command:

< p>

mdadm --create --verbose /dev/md0 --level=stripe --raid-devices=5 /dev/sd[bcdef]

It should work fine. I assume you want to use all the available space on all 5 RAID disks.

> I have a server with 6 4TB drives running Ubuntu 14.04 LTS.
>One of the drives is for system/OS
>I want to use the other 5 drives as close as possible to 20TB of storage space
>This is a short-term data analysis project, so RAID 0 is good
> I used fdisk to create a ~4TB partition on each of the 5 drives

After running mdadm to create a RAID 0 array, the result was just a 10TB device on /dev/md0. The size I was expecting Half of it!

This is the command I used to create the array:

mdadm --create --verbose /dev/md0 --level=stripe --raid -devices=5 /dev/sd[bcdef]1

The following is the output of fdisk -l. Any ideas on why I can’t get more space from the drive? 

Disk /dev/sda: 4000.8 GB, 4000787030016 bytes
255 heads, 63 sectors/track, 486401 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sda1 1 4294967295 2147483647+ ee GPT

Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes< br />90 heads, 3 sectors/track, 28940878 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xda4f04e2

Device Boot Start End Blocks Id System
/dev/sdb1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sdc: 4000.8 GB, 4000787030016 bytes
25 head s, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/ O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc9e57616

Device Boot Start End Blocks Id System
/dev/sdc1 2048 4294967294 2147482623+ 83 Linux 

Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x53bed1ab
< br />Device Boot Start End Blocks Id System
/dev/sdd1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sde: 4000.8 GB, 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
U nits = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disk identifier: 0xbc5c1069

Device Boot Start End Blocks Id System
/dev/sde1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/sdf: 4000.8 GB, 4000787030016 bytes
25 heads, 3 sectors/track, 104187162 cylinders, total 7814037168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4801480c

Device Boot Start End Blocks Id System
/dev/ sdf1 2048 4294967294 2147482623+ 83 Linux

Disk /dev/md0: 10995.1 GB, 10995108413440 bytes
2 heads, 4 sectors/track, -1610614656 cylinders, total 21474821120 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/phys ical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 2621440 bytes
Disk identifier: 0x00000000

Disk /dev/md0 doesn' t contain a valid partition table

Delete 1: from the end of the command: 

mdadm - create --verbose /dev/md0 --level=stripe --raid-devices=5 /dev/sd[bcdef]

should work fine. I assume you want to use all 5 RAID disks All available space.

, , , , , , ,

WordPress database error: [Table 'yf99682.wp_s6mz6tyggq_comments' doesn't exist]
SELECT SQL_CALC_FOUND_ROWS wp_s6mz6tyggq_comments.comment_ID FROM wp_s6mz6tyggq_comments WHERE ( comment_approved = '1' ) AND comment_post_ID = 1402 ORDER BY wp_s6mz6tyggq_comments.comment_date_gmt ASC, wp_s6mz6tyggq_comments.comment_ID ASC

Leave a Comment

Your email address will not be published.