Re: Size of Swap with large phy. mem

In article <9YXb6.9733$9v2.169114_at_quark.idirect.com>,   "Timothy brown" <tbrown_at_tucows.com> wrote:
> If this has been asked before I'm sorry and a simple pointing in the
> right direction would be great!

If you feel you have to say, "If this has been asked before..." try a "Power Search" at http://www.deja.com. If it's been asked before, it's probably there.

> We are getting a few new machines and will be putting a large db on
 them.
> I normally allocate
> Swap space = 2 * Phys. Mem
> Even for machines with 4G of physical memory (is this wrong?)
> Anyway the new machines are going to be E6500's with 30G of memory,
 now
> should I allocate a 60G for swap? (my god thats a lot!)

I agree with Casper's analysis: You need as much swap as you need. These days with cheap memory, and lots of it, blindly allocating 2X physical memory is not a particularly cost-effective measure when it comes to buying disks. You've already discovered this... In the days of yore, swap was mandatory, but Solaris can now run with absolutely no swap.

You need to figure out how much memory your particular application will require during peak times. If that number exceeds 60GB, you need to add _that_ amount of swap space to your system. Depending on how long the duration of "peak," you may also consider adding additional physical memory to your system.

You will want _some_ swap, however. I'd start with a SWAG of about 1G, and watch swap usage with something like top. The system was most likely sized to handle the application in main memory, so only a few small inactive things will get relegated to swap, and most of that 1G will sit empty.

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http://www.deja.com/ Received on Mon Jan 29 2001 - 20:20:35 CET