4

Why does df shows only half the size of a RAID10 array?

view full story
linux-howto

http://serverfault.com – I've created a RAID10 array using 4 75G drives, to create a storage of 150G. After everything finished (including the initial syncing), everything looked good except the output of df -h which showed only 73G storage on the designated mount point. Details: The machine is an m1.large Ubuntu 11.10 instance on Amazon EC2. The 4 drives are EBS drives, each is 75G in size. The RAID10 array was created using the following script: - #!/bin/sh disk1="/dev/sdh1" disk2="/dev/sdh2" disk3="/dev/sdh3" disk4="/dev/sdh4" echo "*** Verifying existence of 4 volumes $disk1, $disk2, $disk3 and $disk4" i (HowTos)

dayu's picture
Submitted by dayu on 02/29/2012 – Made popular on 02/29/2012

Stories similar to Why does df shows only half the size of a RAID10 array?

Basing this question on information I got in Why does df shows only half the size of a RAID10 array?, how should I create a RAID10 array using EBS volumes on Amazon, in a way that will not be redundant too much ?

As the linked question shows, I was using a guide from the 10gen company (that created mongodb) for how to create a raid10 array using EBS.

I encounter an issue with the size of the cre

Basing this question on information I got in Why does df shows only half the size of a RAID10 array?, how should I create a RAID10 array using EBS volumes on Amazon, in a way that will not be redundant too much ?

As the linked question shows, I was using a guide from the 10gen company (that created mongodb) for how to create a raid10 array using EBS.

I encounter an issue with the size of the cre

I'm creating RAID10 array from 6 drives. When created in near layout, e.g.

mdadm --create /dev/md2 --chunk=64 --level=10 --raid-devices=6 --layout=n2 /dev/sda1 ...

Checking stripe size as reported by the system:

cat /sys/devices/virtual/block/md2/queue/optimal_io_size

Result is 196608, as expected, e.g.

Array info:

/dev/md0 -> /dev/sda1 and /dev/sdb1

/dev/md2 -> /dev/sda2 and /dev/sdb2

Partition info:

/boot -> /dev/md0

/ -> /dev/md1

I have two drives that are setup as RAID1 using software RAID on Redhat. I added two additional drives (same size) and I would like to conver the RAID1 to a RAID10. The problem I'm having is adding the last drive to the array.

Bash array manipulation 18 weeks 1 day ago

seeking assistance on comparing two arrays using bash: array1=(disk1, disk2, disk3, disk5, disk7, vol1, vol2, vol3, vol4, vol5) array2=(disk2, disk5 vol2, vol4 ) 1) if two arrays have same elements; EXIT else populate array3 & array4 with elements that are different between array1 & array2 as: array3=(vol1, vol3, vol5) array4=(disk1, disk3, disk7)

thanks in advance

I've seen the advice everywhere (including here and here): keep your OS partition, DB data files and DB transaction logs on separate discs/arrays.

I previously had a raid5 with mdadm using four 2TB drives.

Can I use tw_cli migrate to grow a RAID10 unit where the drives for that unit were each replaced one by one with larger drives? (And the array was rebuilt after each replacement operation.) I am assuming the command to run is as follows:

tw_cli /c0/u0 migrate type=raid10 disk=0-3

The disks in question are 0-3 of course.

So our virtual machine has broken (it's actually a Linux machine in Azure) on which we were running a RAID10 array of 4 disks. It's an ubuntu box. From what I can tell the four data disks are fine, it's just the VM that is screwed.

Now, I could detach the disks from this machine and create a new linux instance, and then attach the disks to that new instance.