WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] [PATCH] [XM-TEST] block device write verify test 2nd att

To: Harry Butterworth <harry@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] [XM-TEST] block device write verify test 2nd attempt
From: Ewan Mellor <ewan@xxxxxxxxxxxxx>
Date: Wed, 24 May 2006 11:20:42 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Wed, 24 May 2006 03:21:02 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <1148387736.10003.26.camel@xxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1148380556.10003.4.camel@xxxxxxxxxxxxxxxxxxxxx> <20060523114019.GB16064@xxxxxxxxxxxxxxxxxxxxxx> <1148387736.10003.26.camel@xxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.9i
On Tue, May 23, 2006 at 01:35:35PM +0100, Harry Butterworth wrote:

> On Tue, 2006-05-23 at 12:40 +0100, Ewan Mellor wrote:
> > On Tue, May 23, 2006 at 11:35:55AM +0100, Harry Butterworth wrote:
> > 
> > > The only difference from the last version of the patch is that the minor
> > > version number in configure.ac is incremented.
> > > 
> > > >From the patch:
> > > 
> > > +# This test imports a ram disk device as a physical device into a domU.
> > > +# The domU initialises the ram disk with data from /dev/urandom and
> > > calculates
> > > +# the md5 checksum of the data (using tee as it is written so as to
> > > avoid
> > > +# reading it back from the device which might potentially mask
> > > problems).
> > > +# The domU is stopped and the md5 checksum of the data on the device is
> > > +# calculated by dom0.  The test succeeds if the checksums match,
> > > indicating
> > > +# that all the data written by domU was sucessfully committed to the
> > > device.
> > > +
> > > 
> > > This patch also enables tee and fancy head in busybox on the ramdisk.  I
> > > have tested the patch with both `make existing' where the tests run but
> > > the new test fails because the ramdisk is missing tee and fancy head and
> > > `make` where the test passes successfully.
> > 
> > Why don't you use dd instead of head -c?
> 
> I tried using dd with a block size of 1 and a count of the right number
> of bytes but the test was very slow.  I didn't want to assume a 512b
> block size and I'm not very good at shell script so didn't manage to
> work out how to do it better.

dd bs=<number> count=1 should do just fine.

> > Why don't you just fix the size of the datablock that you write to the
> > ramdisk, instead of determining the current size of the ramdisk with cat
> > /dev/hda1 | wc -c?
> 
> I wanted to test writing at the device limits.  Sometimes there are off
> by one errors that mean you can't write the last sector of a block
> device.
> 
> cat | wc -c was the most robust way I could think of for getting the
> size.

How about blockdev --getsize64 /dev/ram1?

Ewan.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel