Freebsd 8.0 kmem map too small

[Ben Kelly]

On May 5, 2010, at 9:33 AM, Pawel Jakub Dawidek wrote:

> On Wed, May 05, 2010 at 10:46:31AM +0200, Giulio Ferro wrote:
>> On 05.05.2010 09:52, Jeremy Chadwick wrote:
>> 
>> Nope, it's happened again... Now I've tried to rise vm.kmem_size to 6G...
>> 
>> 
>>> Did you set both vm.kmem_size and vfs.zfs.arc_max, setting the latter to
>>> something *less* than vm.kmem_size?
>>> 
>>> 
>> 
>> Yes.
>> After your suggestion, I set
>> vfs.zfs.arc_max: 3758096384
>> vm.kmem_size: 4G
>> 
>> Now:
>> vfs.zfs.arc_max: 3758096384
>> vm.kmem_size: 6392119296
> 
> Could you try to track down the commit that is causing your problems?
> Could you try 8-STABLE kernel from before r206815?


Are others generally able to run ARC values so close to kmem size?  My experience has been that you really need the ARC to be much smaller than the kmem limit (like 25% or less) due to fragmentation of kmem_map.

- Ben