From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33456) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VoFYN-00080z-VZ for qemu-devel@nongnu.org; Wed, 04 Dec 2013 11:44:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VoFYI-00031E-Dk for qemu-devel@nongnu.org; Wed, 04 Dec 2013 11:43:59 -0500 Received: from mail-ea0-x235.google.com ([2a00:1450:4013:c01::235]:50767) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VoFYI-000314-70 for qemu-devel@nongnu.org; Wed, 04 Dec 2013 11:43:54 -0500 Received: by mail-ea0-f181.google.com with SMTP id m10so10819620eaj.40 for ; Wed, 04 Dec 2013 08:43:53 -0800 (PST) Date: Wed, 4 Dec 2013 17:43:49 +0100 From: Stefan Hajnoczi Message-ID: <20131204164349.GE27759@stefanha-thinkpad.redhat.com> References: <1385546829-3839-1-git-send-email-pl@kamp.de> <1385546829-3839-9-git-send-email-pl@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1385546829-3839-9-git-send-email-pl@kamp.de> Subject: Re: [Qemu-devel] [PATCHv3 1.8 8/9] qemu-img: increase min_sparse to 128 sectors (64kb) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: kwolf@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On Wed, Nov 27, 2013 at 11:07:08AM +0100, Peter Lieven wrote: > Suggested-by: Paolo Bonzini > Reviewed-by: Paolo Bonzini > Signed-off-by: Peter Lieven > --- > qemu-img.c | 4 ++-- > qemu-img.texi | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index 9bb1f6f..8b5f3da 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -100,7 +100,7 @@ static void help(void) > " '-h' with or without a command shows this help and lists the supported formats\n" > " '-p' show progress of command (only certain commands)\n" > " '-q' use Quiet mode - do not print any output (except errors)\n" > - " '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n" > + " '-S' indicates the consecutive number of bytes (defaults to 64k) that must\n" > " contain only zeros for qemu-img to create a sparse image during\n" > " conversion. If the number of bytes is 0, the source will not be scanned for\n" > " unallocated or zero sectors, and the destination image will always be\n" > @@ -1141,7 +1141,7 @@ static int img_convert(int argc, char **argv) > QEMUOptionParameter *out_baseimg_param; > char *options = NULL; > const char *snapshot_name = NULL; > - int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */ > + int min_sparse = 128; /* Need at least 64k of zeros for sparse detection */ > bool quiet = false; > Error *local_err = NULL; I guess a sane size would be cluster size. For a raw file 4 KB is reasonable since that's the file system block size. Is it necessary to increase to 64 KB here?