On Tue, Oct 18, 2011 at 8:55 PM, Karanbir Singh mail-lists@karan.org wrote:
On 10/18/2011 04:11 PM, Arun Khan wrote:
You mean, it is not OK to pull out a "functioning" disk? Pulling one disk out of RAID 5 should be OK. Am I missing something?
grab yourself a bunch of usb keys + a usb hub - fire up mdadm on your laptop and use those keys as target disks and see how things work with mdadm and hotswap. Much fun to be had there. I would also recommend using CentOS6.
Thanks for the suggestion - a great way to experiment.
From the feedback on this thread, I am leaning towards h/w raid controller.
Pulling a disk that isnt set bad and deactivated in mdadm can cause some very funky results - best of all, the machine will freeze and you can reinsert the disk boot up and carry on. Worst of all, you will lose all the data on the array.
I agree.
btw, dont think that these issues dont affect hardware raid - they do. its just that the management for these things is slightly more abstracted away and the controllers are better integrated with the disk cages.
About 10 years ago, I had a h/w raid controller go bad (HDDs connected via SCSI cable - no HDD bays involved). The replacement card recreated the RAID array - lost all data. I did have a back up to restore most of the data.
-- Arun Khan