vm_thread_new: kstack allocation failed with many ZFS FS and NFSD

[Thomas Vogt]

Hi Kris

Am 11.03.2008 um 01:30 schrieb Kris Kennaway:
> Thomas Vogt wrote:
>> Hi List(s)
>> I try to simulate real workload for our environment in my lab. The  
>> idea
>> was to create 10k+ ZFS fs with several thousand files on each fs and
>> then measure daily workload performance. Maybe 10k fs sounds silly  
>> but
>> if you need individual quota for every user on a system, 5-10k fs are
>> not unusual for ZFS
>> My script to cerate zfs fs
>> #!/bin/sh
>> i=0; while [ $i != 10000 ]; do zfs create tank/script$i; i=`expr $i +
>> 1`; done
>> My script stopped after creating ~4850 FS with:
>> vm_thread_new: kstack allocation failed
>> vm_thread_new: kstack allocation failed
>> vm_thread_new: kstack allocation failed
>> vm_thread_new: kstack allocation failed
>> vm_thread_new: kstack allocation failed
>> vm_thread_new: kstack allocation failed
>
> Your kernel has run out of memory.  If you cannot tune kmem_size  
> further then it cannot handle this many ZFS filesystems.

Are there no limitation for vm.kmem_size* sysctls? I tried to increase  
vm.kmem_size* with larger values than 1500M but the system paniced in  
the boot process.

Mark Tinguely told me maybe i can edit sys/amd64/include/pmap.h and  
change the line:

- #define KPDPI		 (NPDPEPG-2)	/* kernbase at -2GB */
+ #define KPDPI		 (NPDPEPG-4)	/* kernbase at -4GB */

I will try this. Any idea if this is save?

Regards,
Thomas