Re: [Moosefs-users] mfsmaster performance and hardware

[Robert S. <rsa...@ne...>]

On 8/9/11 12:56 AM, Elliot Finley wrote:
> On Mon, Aug 8, 2011 at 5:24 PM, Robert Sandilands<rsa...@ne...>  wrote:
>> When I run a strace() on mfsmaster on the hour I get the following:
>>
>> rename("changelog.1.mfs", "changelog.2.mfs") = 0
>> rename("changelog.0.mfs", "changelog.1.mfs") = 0
>> clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
>> child_tidptr=0x2b571b910b80) = -1 ENOMEM (Cannot allocate memory)
>> rename("metadata.mfs.back", "metadata.mfs.back.tmp") = 0
>> open("metadata.mfs.back", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 11
>>
>> This indicates fork() is failing with an out of memory error. The system has
>> 11 GB cached and 300 MB free. It only has 6 GB of swap. This indicates that
>> clone() ( also known as fork() ) may be trying to test whether the whole
>> process will fit into memory when cloned. Which implies that the memory
>> requirement is actually double than what is commonly believed.
> Just out of curiosity, what OS are you using?
>
> Elliot
Linux (Centos 5.6 64-bit).

Robert