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. 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. 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. - KB