(original article)


22 February 2010, 01:03 UTC

Hey there,

first of all I want to thank Neil and all other developers of mdadm for their great work. I have been using mdadm for several years now and my arrays have survived two disk-faults flawlessly - from the notification-email to rebuilding the array everything went as it should.

I have a question regarding my raid6-array, consisting of 7 1TB-disks providing a single lvm-physical volume. I plan to expand that array with a 1.5TB-disk and want to make sure that I got everything written here and on the mailing list right:

- If I grow that array after adding the new 1.5TB-disk to it, only 1TB of the new disk will be used and the array-size will increase by 1TB. (Do I have to issue some special commands when growing or will mdadm automatically just use 1TB of the 1.5TB-disk?)

- If I resize the lvm-physical volume the array provides, the 1TB will become usable by lvm.

Is that correct?

Then I got another question: To grow a raid6-array, I need mdadm past version 3.x. Currently, the array is on a debian-server running a year or so without reboot, therefore it runs on mdadm-2.6.x. I recently updated the mdadm-package to the current version 3.1.1 using aptitude. Is a reboot necessary for the grow-feature to become available or does it suffice to just stop and start the array (or is neither of these actions necessary)?

Thank you all for your help!