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From: Dieter<freebsd@sopwith.solgatos.com>
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Subject: kern/106340: Need to control disk write cache on per-disk basis
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>Number:         106340
>Category:       kern
>Synopsis:       Need to control disk write cache on per-disk basis
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Mon Dec 04 18:30:14 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Dieter
>Release:        6.0
>Organization:
>Environment:
>Description:
FreeBSD only allows setting disk write cache mode on a system wide basis,
and only at boot time.  NetBSD allows setting the disk write cache mode
of each disk individually, and does not require a reboot.  See the NetBSD
dkctl(8) man page.

There are many times it would be very useful to be able to put one disk
into write-back mode and get the 10x speedup.  But we cannot do this in
FreeBSD because putting all the filesystems at risk of getting scrambled
is unacceptable.
>How-To-Repeat:

>Fix:

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