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Subject: Re: tmpfs out of space (ZFS related?)
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On 11/21/10 23:19, Eir Nym wrote:
> On 22 November 2010 01:00, Eir Nym<eirnym@gmail.com>  wrote:
>> On 22 November 2010 00:47, Bruce Cran<bruce@cran.org.uk>  wrote:
>>> On Mon, 22 Nov 2010 00:43:03 +0300
>>> Eir Nym<eirnym@gmail.com>  wrote:
>>>
>>>> Which type of MFS do you use? I think you shold use "swap-backed" for
>>>> your /tmp, not "malloc-based". Last type is only for in-kernel file
>>>> system.
>>>
>>> It's tmpfs(5), not md(4).
>>>
>>
>
> I wonder if you can create FIFO and sockets with md(4). md(4) is
> geometry, not filesystem.

md is a GEOM class which presents several types of devices backed by 
virtual memory. You can create file systems on top of those and mount them.

The downside is that each of those layers has its own copy of the 
original data (and them some).

tmpfs OTOH is a "real" memory file system, without the need for a 
backing device, and it is more efficient with respect to data copies 
(not perfect - it still AFAIK has to maintain something like 2 copies).

> tmpfs(5) doesn't support this file types as I can see in FreeBSD source code.

Maybe it is handled by default code, but they are supported. I have used 
tmpfs extensively for the last few years for mostly static servers (i.e. 
/tmp contains some sockets, a small number of short-lived temporary 
files, etc) - and it so far worked very well. This is actually the first 
time it failed me in some way.