kern/160811: Cannot change gmirror provider priority in RELENG_7 (r196879)

[Eugene Grosbein]

>Number:         160811
>Category:       kern
>Synopsis:       Cannot change gmirror provider priority in RELENG_7 (r196879)
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sun Sep 18 21:30:10 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Eugene Grosbein
>Release:        FreeBSD 7
>Organization:
RDTC JSC
>Environment:
System: FreeBSD 7.2-RELEASE

>Description:
	When first of gmirror's drives in some old server started dying
	(read errors, SMART offline read test fails) I was forced
	to prepare new hardware to replace this 2-drive PATA system.

	But, it appears this is not possible to make final dumps
	of its file systems as dump(8) hangs the whole box while reading
	failing drive.

	I was going to switch gmirror to 'prefer' balance algorithm
	to disable reads from first drive. I could not achieve this
	as /sbin/gmirror in RELENG_7 does not allow to change provider
	priorities (both drives priorities are zeroes).

>How-To-Repeat:
	gmirror(8) manual page shows no support for "gmirror -p"
	as in 8.x and 9.x branches due to missed SVN r196879 merge.
>Fix:

	Please perform merge of r196879 to RELENG_7.
	I've did it manually, it applies cleanly and works just fine,
	I was able to make second drive more preferable with this change.

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