RAID 5 performance after one failed hard drive

[It's Not Lupus]

What is the performance like for a RAID 5 array after one hard drive fails? Would I be able to transfer data from that array to another at a decent speed without rebuilding?

I have not used RAID before and am thinking of setting up an old computer as some kind of offline storage for some non-important data. I have backups etc. I am just curious.

 

[PliotronX]

I think read performance is hit by one third and write performance is unaffected until a fresh drive is popped in then all performance goes down the toilet until the array is rebuilt. The rebuilding part is why I wouldn't use raid-5 on anything larger than 600GB (15K). Much prefer 10 these days...

edit- I should add that a hot spare will eliminate any performance hit while replacing the bad one and further protect against what's call a puncture in the remaining drives. RAID-6 is very similar to RAID-5 with a hot spare but I prefer the latter for performance.