[Bug 828421] [NEW] Create new RAID1 array without resync

[Robert Voje]

Public bug reported:

I tried several times to create a RAID1 array, but was haunted by the
resync, that is taking MANY hours to finish.

Finally, I found a reference to a parameter on the web: --assume-clean
Of course, this parameter stated that it only should be used "when you know what you're doing".

Then I answered myself: I know what I'm doing. I'm creating a whole new
RAID1 array, with blank disks and all.

The result was an auto creation of a "md_d0" array, which I had to delete, then it created a array named "md_0p1" or something.
The whole clue is, that mdadm never gave up on the original array, it just renamed it, and I had to delete the member disks from each array that mdadm was auto-creating.

The main question is still:
Why should I wait 3-6 hours for the damn daemon to replicate random data from one partition to another.

The situation is, that I have 2 clean disks. What I weant to do is to
create a raid1 array on them, but mdadm still demands to sync them.

Is'nt there a way to "blank" new raid arrays, so we does not have to
wait several hours on resync?

Just now, I'm trying this on a couple of 500GB disks, but tomorrow I'll
receive two 2TB disks wich I also want as a RAID1 array, and I fear that
the rest of the week will go by synchronizing my empty new disks.

** Affects: mdadm (Ubuntu)
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to mdadm in Ubuntu.
https://bugs.launchpad.net/bugs/828421

Title:
  Create new RAID1 array without resync

Status in “mdadm” package in Ubuntu:
  New

Bug description:
  I tried several times to create a RAID1 array, but was haunted by the
  resync, that is taking MANY hours to finish.

  Finally, I found a reference to a parameter on the web: --assume-clean
  Of course, this parameter stated that it only should be used "when you know what you're doing".

  Then I answered myself: I know what I'm doing. I'm creating a whole
  new RAID1 array, with blank disks and all.

  The result was an auto creation of a "md_d0" array, which I had to delete, then it created a array named "md_0p1" or something.
  The whole clue is, that mdadm never gave up on the original array, it just renamed it, and I had to delete the member disks from each array that mdadm was auto-creating.

  The main question is still:
  Why should I wait 3-6 hours for the damn daemon to replicate random data from one partition to another.

  The situation is, that I have 2 clean disks. What I weant to do is to
  create a raid1 array on them, but mdadm still demands to sync them.

  Is'nt there a way to "blank" new raid arrays, so we does not have to
  wait several hours on resync?

  Just now, I'm trying this on a couple of 500GB disks, but tomorrow
  I'll receive two 2TB disks wich I also want as a RAID1 array, and I
  fear that the rest of the week will go by synchronizing my empty new
  disks.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/828421/+subscriptions