Re: OOM on quotacheck (again?)

Volker
2012-09-24T14:46:12Z

Hi,

>> Could you slightly elaborate on that or give me a link or two which
>> explain the matter?
>
> The kernel segment is limited to 960MB of RAM on ia32 bit machines
> unless you build with special config options that allow for up to
> 3GB of kernel memory. The trade off is that you've only got 4GB of
> RAM in teh process address space, so by default you have 3GB of RAM
> for each process (i.e. 960MB/3GB kernel/user split). If you change
> that to a 3GB/1GB split, you'll have problems with applications
> that are memory hogs running out of memory.

Interesting!

> As to the memory used by the inode cache, inodes tend to use between
> 1-1.5k of RAM each. Hence for a 960MB kernel segment, you *might* be
> able to cache 500,000 inodes if you don't cache anything else.
> Typically it will be 25-30% of that number (200-300MB of RAM in
> caching inodes during filesystem traversal). Seeing as you have
> millions of inodes, that's way more than you can cache in available
> kernel memory...

Great! That answered all my questions! Thanks a lot!

3.6.0-rc6-x64 ist currently running fine on 6 machines.

-volker