Byron,
All,

On Wednesday 23 September 2009 18:38:00 Byron Guernsey wrote:
> In my application I have to run many capture sets- as many as 1000,  
> with each being as large as about 28GB.  After a capture completes, I  
> can move it off the spool storage and onto a slower mechanical hard  
> disc.  This is intended to free up space on the SSD for the next  
> capture set.
[--SNIP--]
> I know what you're thinking- a RAM drive is really what I need, and I  
> agree.  But a $150 SSD is cheaper than a server-class motherboard and  
> 32GB of ram to use for a ram drive.  So I'm working within a budget  
> and an SSD with NILFS works fine, except for when I need to delete the  
> files and reclaim space.

I don't think you even need a file system for this...

If your capture set is one big file, then directly use the raw device:
- add the user running the capture to the group 'disk'
- have the SSD raw device be group-writeable
- direct your capture output to the raw device
- copy the raw device content to long-term storage (eg with dd)

If you use multiple files for your capture:
- do you know in advance the number of files?
- is this number small (eg. <16)?
- do you know in advance the size of each file?
- if you answered yes to all three questions, then create appropriate
  partitions on your device, and direct each capture "stream" to one
  partition, as presented above.
- if you answered no to any of the above, then you'll indeed need a
  file system.

Maybe unomuting and re-mounting the partition would be a solution,
but you'd need root access, or make a small suid program that does
the mount/umount for you.

Regards,
Yann E. MORIN.

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