David Boyes <[EMAIL PROTECTED]> wrote:
> On Mon, Apr 22, 2002 at 04:26:39PM -0500, Holly, Jason wrote:
> > has anyone established mean-time-between-failure numbers for linux instances
> > running under vm? anything general would be good information. i'm curious
> > about disk, memory or other system failures that compromise the vm
> > instances.
>
> The record for us is about 9 months for a single Linux image. Average
> is about 3-4 months between reboots, depending on what's running in
> them -- things that suck up lots of memory like Websphere tend to
> shorten the lifespan of the machine by fragmenting storage. Machines
> that get a lot of interactive use tend to collect a few zombies after
> a while, so reboots become a reasonably good idea after a while.
I have to say that I'm a little surprised at that recommendation.
Let me see if I understand... you're saying that you need to
reboot your Linux images about every 9 months because the Linux
virtual memory manager has issues? I hadn't heard that before...
Seems like I've heard lots of tales of people with Linux up
much longer than 9 months... doing web services, etc... do you
think your 9 month figure is a function of the 390 version
of Linux, or Linux in general? That is, would you recommend
rebooting a PC version of Linux on the same interval (given
the same workload?)
We don't reboot our machines unless there is some configuration
change... but, we don't do highly interactive things on them,
just product builds every now-and-then.
Also - just to ask - what about the BSD variants - would you
also recommend 9 months for them? It's my understanding that
the virtual memory manager in FreeBSD is better than Linux, for
example, and perhaps might not suffer the fragmentation issues?
[Of course, that may be a biased understanding... I have no
evidence to back that up.]
>
> For the VM side, I know of sites with uptimes measured in years;
Yes - this is much better! :-) And, I would expect it from
Linux (even today's Linux) too...
Could you relate more about this 9 month figure? Do you have
specific instances where it was required, that you can share
of course...
- Thanks! -
- Dave Rivers -
--
[EMAIL PROTECTED] Work: (919) 676-0847
Get your mainframe programming tools at http://www.dignus.com
