about faulty spare-disk interrupts synchronization

Hi,
Is it intended that when a spare disk status gets faulty (detached from raid or really faulty) 
synchronization is interrupted ? We found that case several days ago with kernel version of 2.6.24, 
after we unplugged a spare disk of a raid5 which had bitmap and was recovering, the spare disk 
status became faulty  and synchronization restarted from 0%. 

Looking into the md code, i find that in md/md.c/md_error(), it doesn't make a difference between 
spare disks and normal disks. Should we make a faulty spare disk not interrupt raid synchronization ?
Disks nowadays have become much larger, and recovering one disk may cost several hours or even longer.

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spren.gm@gmail.com
2009-12-23