tmpfs runs out of space on 8.2pre-release, zfs related?

[Ronald Klop]

On Sun, 02 Jan 2011 09:41:04 +0100, miyamoto moesasji  
<miyamoto.31b at gmail.com> wrote:

> miyamoto moesasji <miyamoto.31b <at> gmail.com> writes:
>
>>
>> In setting up tmpfs (so not tmpmfs) on a machine that is using
>> zfs(v15, zfs v4) on 8.2prerelease I run out of space on the tmpfs when
>> copying a file of ~4.6 GB file from the zfs-filesystem to the memory
>> disk. This machine has 8GB of memory backed by swap on the harddisk,
>> so I expected the file to copy to memory without problems.
>>
>
> ....this is in fact worse than I first thought. After leaving the
> machine running overnight the tmpfs is reduced to a size of 4K, which
> shows that tmpfs is in fact
> completely unusable for me. See the output of df:
> ---
> hge at PulsarX4:~/ > df -hi /tmp
> Filesystem    Size    Used   Avail Capacity iused ifree %iused  Mounted  
> on
> tmpfs         4.0K    4.0K      0B   100%      18     0  100%   /tmp
> ---
>
> Relevant zfs-stats info:
> ---
> System Memory Statistics:
> 	Physical Memory:			8161.74M
> 	Kernel Memory:				4117.40M
> 	DATA:				99.29%	4088.07M
> 	TEXT:				0.71%	29.33M
>
> ARC Size:
> 	Current Size (arcsize):		63.58%	4370.60M
> 	Target Size (Adaptive, c):	100.00%	6874.44M
> 	Min Size (Hard Limit, c_min):	12.50%	859.31M
> 	Max Size (High Water, c_max):	~8:1	6874.44M
> ---
>
> I'm not sure what triggered this further reduction in size; but the
> above 4K size is probably important to show how dramatic this goes
> wrong.

Is it possible that some program is filling a file (on your tmpfs) which  
is deleted?
You will not see it with df or ls, but it still takes space on the fs,  
until the application closes the file.

Ronald.