[sheepdog] [PATCH] sheep: check resource limit at startup

[MORITA Kazutaka]

At Mon, 28 Jan 2013 14:47:41 +0800,
Liu Yuan wrote:
> 
> From: Liu Yuan <tailai.ly at taobao.com>
> 
> Sheep daemon is FD hungry and can't survive for EMFILE.
> 1024 is default for NOFILE on most distributions, which is very
> dangerous to run Sheepdog cluster. Let's give a warning on this.
> 
> Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
> ---
>  sheep/sheep.c |   29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/sheep/sheep.c b/sheep/sheep.c
> index f2c7bcd..5c5bcc5 100644
> --- a/sheep/sheep.c
> +++ b/sheep/sheep.c
> @@ -26,6 +26,7 @@
>  #include <fcntl.h>
>  #include <errno.h>
>  #include <arpa/inet.h>
> +#include <sys/resource.h>
>  
>  #include "sheep_priv.h"
>  #include "trace/trace.h"
> @@ -385,6 +386,33 @@ static int init_work_queues(void)
>  	return 0;
>  }
>  
> +#define SD_RLIM_NOFILE 65536

Please explain why you think 65536 is enough.  Does it an enough
number even if many VMs send IO requests at the same time?  I've hit
the FD limitation when doing the test.

BTW, Is it difficult to modify sheepdog so that it doesn't use so many
FDs?

Thanks,

Kazutaka