Re: [PATCH] qemu-img: Add nocache command line option

[Avi Kivity <avi@redhat.com>]

On 06/14/2011 03:09 PM, Federico Simoncelli wrote:
> qemu-img currently writes images using writeback and filling up
> the cache buffers which are then flushed by the kernel preventing
> other processes from accessing the storage.
> This is particularly bad in cluster environments where time-based
> algorithms might be in place and accessing the storage within
> certain timeouts is critical.
> This patch adds the option to use nocache when other solutions
> (eg: cgroups) are not available.
>

Please copy qemu-devel@nongnu.org as this is not a kvm-specific patch.

> diff --git a/qemu-img.c b/qemu-img.c
> index 4f162d1..c10e4a6 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -78,6 +78,7 @@ static void help(void)
>              "       rebasing in this case (useful for renaming the backing file)\n"
>              "  '-h' with or without a command shows this help and lists the supported formats\n"
>              "  '-p' show progress of command (only certain commands)\n"
> +           "  '-t' use write-through (no cache), valid with: convert, commit and rebase\n"
>              "\n"
>              "Parameters to snapshot subcommand:\n"
>              "  'snapshot' is the name of the snapshot to create, apply or delete\n"

IMO better to use the existing qemu option format, say -o 
cache=writeback|writethrough|none|volatile.

-- 
error compiling committee.c: too many arguments to function