On 2/16/2017 9:18 PM, Keith Keller wrote:
On 2017-02-15, John R Piercepierce@hogranch.com wrote:
On 2/14/2017 4:48 PM,tdukes@palmettoshopper.com wrote:
3 - Can additional drive(s) be added later with a changein RAID level without current data loss?
Only some systems support that sort of restriping, and its a dangerous activity (if the power fails or system crashes midway through the restriping operation, its probably not restartable, you quite likely will lose the whole volume)
Doesn't mdraid support changing RAID levels? I think it will even do it reasonably safely (though still better not to have a power failure!). I have a vague memory of adding a drive to a RAID5 and converting it to a RAID6 but I could be misremembering.
any such operation requires the entire raid to be re-slivered, stripe by stripe, as ALL the data moves around. on a large raid made from multi-terabyte drives, this would take DAYS.