[CentOS] Swap Considerations

Thu Mar 1 06:32:27 UTC 2007
Feizhou <feizhou at graffiti.net>

> heh, it does appear that the conversation missed the boat.  Actually,
> I asked RedHat (when we supposedly had their attention) years ago
> about what the real swap requirements for linux where, or what were
> the best practices, and what should we monitor concerning swap for
> alarming purposes and never really got a good answer.  Those were back
> in the RH 9 days, but at anyrate I would be interested in hearing
> oppinions of how one should use swap if they were to use it.

With the presence of LVM, I would make a mirror array, make that a PV 
and later make a lv for the swap partition.

I think monitoring swap comes down to two things: strange memory use and 
whether there is a lot of stuff going in and out of swap and the amount 
of data. For I/O intensive servers, you don't want to see swap being 
used so monitoring swap usage can help to fine tune no. of processes or 
whatever to keep the box from using swap if it does use swap.

So I personally only care about swap if using it gets in the way 
(usually servers) and if my box does not have enough RAM for the 
applications I have to open where disk I/O is not critical (usually