memory warnings r240891 | dmesg

[Darrel]

>> (30) @ 12:01:50> swapinfo
>> Device          1K-blocks     Used    Avail Capacity
>> /dev/zvol/bigD/swap   4194304        0  4194304     0%
>> /dev/gpt/swap0.eli   3145728        0  3145728     0%
>> /dev/gpt/swap1.eli   3145728        0  3145728     0%
>> Total            10485760        0 10485760     0%
> [...]
>> *************************************************************
>> FreeBSD 10.0-CURRENT #1 r240891: Tue Sep 25 00:51:03 EDT 2012

>> warning: increase kern.maxswzone or reduce amount of swap.
>>
>> *************************************************************
>>
>> Apparently kern.maxswzone is currently equal to 0.  How might I tweak it
>> just enough to fix this?
>
> So, reduce amount of swap :)
>
> This is because kernel needs some memory to manage swap too.
> Currently for amd64 this roughly reduces to the following rule
> (My apologies in advance for the extra simplification):
>
> 100MB RAM per 800MB swap space.
>
> So, with your current amount of RAM (893MB) it is recommended to setup
> no more than 7144 MB of swap. [1]
>

Thanks for the good ideas.  Thus far,

#  zfs get volsize bigD/swap
NAME       PROPERTY  VALUE    SOURCE
bigD/swap  volsize   4G       local

# zfs set volsize=1100m bigD/swap

# zfs get volsize bigD/swap
NAME       PROPERTY  VALUE    SOURCE
bigD/swap  volsize   1.07G    local

(73) @ 6:55:44> swapinfo -h
Device          1K-blocks     Used    Avail Capacity
/dev/#C:0x6c      4194304     808k       4G     0%
/dev/gpt/swap0.eli   3145728     772k       3G     0%
/dev/gpt/swap1.eli   3145728     800k       3G     0%
Total            10485760     2.3M      10G     0%

- yes, it appeared that something weird happened to the file name

# zfs destroy -V bigD/swap
- file in use or some error

# reboot

# swapinfo -h
Device          1K-blocks     Used    Avail Capacity
/dev/zvol/bigD/swap   1126400       0B     1.1G     0%
/dev/gpt/swap0.eli   3145728       0B     3.0G     0%
/dev/gpt/swap1.eli   3145728       0B     3.0G     0%
Total             7417856       0B     7.1G     0%

So the zvol swap size was reduced, but the swzone error still exists.

Also, the zfs create and destroy commands availed nothing- perhaps there
were subsequent or subcommands to run there.

Is there a good method to reduce the encrypted swap, perhaps?  I might 
like to have a total of 3g encrypted swap plus 3g zvol swap.

Darrel