Jump to content
XPEnology Community

SHR non-hot-swap disk failure simulation


Recommended Posts

Hi all,


I have 2 x 8TB configured as SHR with 1-disk fault tolerance. To make sure that the raid function is working I was looking for a way to test this. When working on a linux computer i could Force-fail by software. Newer versions of raidtools come with a raidsetfaulty command. By using raidsetfaulty you can just simulate a drive failure without unplugging things off.


Is this also possible when running XPEnology? Any other suggestions on how to simulate this on a non-hot-swap system (HP N54L bios not modified)


Another question that is bugging me is this: Right now i have only 2 disks, and am assuming that the current setup is ment to work in a situation where disk 1 would fail, the second disk just takes over. This would mean that there is already a synced copy of the data available on disk 2, or not?


And what would the case be when I add a third 8TB HDD to the mix. The final goal would be to have 2 x 8TB = 16 TB data storage available + 1 x 8TB for 1-disk fault tolerance. It would be my assumption that if disk 1 or 2 would fail, disk 3 would step in. But then again the question would be, if I have data spread over disk 1 and 2, how does SHR knows what data to mirror on disk 3? Is there actual data on disk 3?


Thanks for clearing this technical dilema :smile:

Link to comment
Share on other sites

Not sure in your commands question. I would just turn off the NAS. Unplug a disk and turn on.


About your 2 disk vs 3 disk question. If you have 2 disks is like Raid1, if you have 3 disks is kinda like raid5 (I think?)


Anyway you always (by default) have 1 disk tolerance. That doesn't mean if "disk 1 fails then the disk 2 will come in". Its more like if any drives fail (just one of course) your data will still be there.


With 3 drives is the same, disk 1,2 or 3 can fail and you will still be able to read your data.


Just google SHR or Raid and have a read.

Link to comment
Share on other sites

"Its more like if any drives fail (just one of course) your data will still be there" ...


Haha !!! And that is the technical wonder I'm trying to understand :smile:. If I have 16TB of data, and only 8TB for failover... how does this work? If I only have a one-on-one failover system (like I used to have in Linux : one disk has its own "second" disk for raid). All data is continiously synced. If one disk goes belly up, the second already has ALL data. But I can't figure out how SHR does this with 16TB agains 8TB failover.

Link to comment
Share on other sites

  • Create New...