kern/99989: detaching disk

[bymer]

>Number:         99989
>Category:       kern
>Synopsis:       detaching disk
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jul 09 23:10:19 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     bymer
>Release:        FreeBSD 6.1 RELEASE - STABLE i386
>Organization:
>Environment:
>Description:
I have several computers of different configurations (other
motherboards, controllers). Each have 14-20 hdd devices (ATA & SATA).
Under heavy load, all of them periodically crashed (every 10-20 hours) with "disk detached" (random disk id) error.

subdisk10: detached
ad10: detached
g_vfs_done():ad10s1h[READ(offset=289109770240, length=65536)]error = 6
g_vfs_done():ad10s1h[READ(offset=289297481728, length=131072)]error = 6
g_vfs_done():ad10s1h[READ(offset=296795766784, length=131072)]error = 6
 -- skipped --

After it kernel panic (panic: vinvalbuf: dirty bufs) or hang. After reboot process all working fine.

It's appear on all FreeBSD 6 versions, from 6.0 RELEASE to 6.1-STABLE.

>How-To-Repeat:
See full description.
>Fix:
I understand that disk I/O error happened, but detaching disk it's not a good idea. It's good to control detach process from sysctl variable or similar this.

>Release-Note:
>Audit-Trail:
>Unformatted: