On Tue, 14 Dec 2004 10:57:06 -0600, Tom Shilson <[EMAIL PROTECTED]> wrote:

> > You don't mean to use VDISK for that, do you?
>
> That is what I meant but I have been educated.  Real storage is too
> valuable to spend on /tmp.

It was easy for me to ask because it's so intuitive, and I hope I did
not sound as if that were the most stupid idea...  For most people
VDISK is cheap because it does not require talking to the person who
manages the disks.

As we know VDISK will eventually land on CP paging devices and the
disks for that are about the same cost as any other disk space (about
the same, because you want to keep paging utilization under 50% to
allow for efficient block paging). So it did seem like a good idea
because you share the unused space in your /tmp allocation among all
Linux servers.

One of the things that makes this work out less well in the end is the
allocation strategy of Linux on that file system. Instead of re-using
freed blocks, it will prefer to allocate fresh blocks, so over time
you will have touched every block in your /tmp file system. That is
not nice in a shared environment.

And as you say there is the issue of using real memory for the data.
But with MDC and Linux page cache doing that, you can not always avoid
that.

http://www.mail-archive.com/[email protected]/msg21730.html

YMMV: I am sure we can come up with examples where using VDISK for
/tmp is a huge benefit...
--
Rob van der Heij                  rvdheij @ gmail.com

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