OK To Use Drive While RAID Rebuilding?

[louie29]

I need to replace a drive in a Linkstation Pro Duo RAID1 2x2TB.  Internet information I've seen says it's fine to use drives while RAID is rebuilding. My testing with another Pro Duo seems to indicate it's fine also. 

But in the web interface after starting the rebuild it says "cannot change all of the configurations until changing Raid Array is completed. Also share folder service is not working."

But that's not true.  Share folder service is working while it's rebuilding (and I hope it's left that way).  That was the whole point of my test.  I was working the test drive pretty hard from multiple computers, read and write, while the RAID was rebuilding, and it seemed fine.  But the message got me thinking maybe Buffalo doesn't want you to use the drive while it's rebuilding.  Is that true? and if so Why? if it seems to work fine, and other manufacturers don't have a problem with it.

Also, does anyone know how long it takes to rebuild RAID1 on a 2x2TB Pro Duo?  Thanks.

[louie29]

I ended up rebuilding the RAID without simultaneously using the Share, but I don't think I'd be hesitant to use the Share next time around.  Couldn't find any issues doing that.

FWIW, the RAID1 rebuild took the following times on ProDuo with current firmware, 7200rpm drives:

2 x 2TB:  11 hours.
2 x 1TB:  5.5 hours.

Same times that it takes to do RAID scans on those units (which I guess makes sense, but I didn't know.  I wasn't sure if it mattered how full the drives were, but it doesn't seem to matter.  For the 2 x 2TB, it takes 11 hours whether they're full or near empty.)