Luca Berra wrote:
many people find it easier to understand if raid partitions are set to 0XFD. kernel autodetection is broken and should not be relied upon.
Could you clarify what is broken?
I understood that it was simplistic (ie if you have a raid0 built over a raid5
or something exotic then it may have problems) but essentially worked.
Could it be :
* broken for complex raid on raid
* broken for root devices
* fine for 'simple', non-root devices
>4) I guess the partitions itself doesn't have to be formated as the >filesystem is on the RAID-level. Is that correct? compulsory!
I meant, the /dev/mdX has to be formatted, not the individual partitions. Still right?
compulsory! if you do anything on the individual components you'll damage data.
i think it will be marked faulty, not removed.>5) Removing a disk requires that I do a "mdadm -r" on all the partitions
>that is involved in a RAID array. I attempt to by a hot-swap capable
>controler, so what happens if I just pull out the disk without this
>manual removal command?
as far as md is concerned the disk disappeared.
I _think_ this is just like mdadm -r.
yep - you're right, I remember now. You have to mdadm -r remove it and re-add it once you restore the disk.
So I could actually just pull out the disk, insert a new one and do a "mdadm -a /dev/mdX /dev/sdY"? The RAID system won't detect the newly inserted disk itself?
no, think of it as flexibility. if you want you can build something using the "hotplug" subsystem.
or: no, it would be mighty strange if the raid subsystem just grabbed every new disk it saw... Think of what would happen when I insert my camera's compact flash card and it suddenly gets used as a hot spare <grin>
I'll leave Luca's last word - although it's also worth re-reading Peter's first words!!
David
one last word: never trust howtos (they should be called howidid), they have the tendency to apply to the author configuration, not yours. general documentation is far more accurate.
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