9.0 crash, ssd or filesystem problem?

[Gary Aitken]

On 11/16/12 21:38, Warren Block wrote:
> On Fri, 16 Nov 2012, Gary Aitken wrote:
> 
>> On 11/16/12 12:10, Warren Block wrote:
>>
>>> Additional SSD suggestions: when creating partitions, leave out the swap
>>> partition.  If you have lots of memory, leave out the /tmp partition. Add
>>> that extra space to the /usr partition.
>>>
>>> Format the UFS filesystems with -Ut, for soft updates and TRIM support.
>>> (Make sure your SSD supports TRIM, almost all do.)  (I don't use soft
>>> updates journaling.)
>>>
>>> Use dd(1) to make a zero-filled file on /usr somewhere, say /usr/swap.
>>> Make it the size you want swap to be, and do not make it a sparse file.
>>> Tell the system to use the swapfile in /etc/rc.conf:
>>>
>>>    swapfile="/usr/swap"
>>>
>>> Use tmpfs for /tmp in /etc/fstab:
>>>
>>>    tmpfs        /tmp    tmpfs    rw,mode=01777    0    0

When using the above in /etc/fstab to establish a tmp file, 
how does the size of /tmp get established?
Is it limited only by the available swap,
or is it possible to put an upper bound on it that is smaller than swap?

e.g. if I built it manually:
  mdconfig -a -t swap -s 1g -u 1
  newfs -U /dev/md1
  mount /dev/md1 /tmp
  chmod 1777 /tmp

wouldn't it be limited to 1g of swap space?

Gary