Re: Swapping on Solaris

/tmp doesn't seem to be much of a problem. I have about 1k worth of data in
there and 72k in /var/tmp.

Would turning swap off help in tuning the database in this regard? top is
reporting that there's 1.25GB of RAM free on a 2GB system so, in my
estimation, there's no need for PostgreSQL to be swapped unless that free
memory is Solaris caching files in RAM.

Kevin

----- Original Message -----
From: "Greg Spiegelberg" <gspiegelberg(at)cranel(dot)com>
To: <stange(at)rentec(dot)com>
Cc: "Kevin Schroeder" <kschroeder(at)mirageworks(dot)com>;
<pgsql-performance(at)postgresql(dot)org>
Sent: Wednesday, January 19, 2005 9:07 AM
Subject: Re: [PERFORM] Swapping on Solaris

> Alan Stange wrote:
>>
>> Note that files in /tmp are usually in a tmpfs file system. These files
>> may be the usage of swap that you're seeing (as they will be paged out on
>> an active system with some memory pressure)
>
> You can do a couple things with /tmp. Create a separate file system
> for it so it will have zero impact on swap and use the "noatime" mount
> option. Alternatively, limit the size of /tmp using the mount option
> "size=MBm" replacing "MB" with the size you want it to be in MBytes. If
> your application uses /tmp heavily, be sure to put it on a speedy,
> local LUN.
>
>
>> Finally, just as everyone suggests upgrading to newer postgresql
>> releases, you probably want to get to a newer Solaris release.
>
> If you really want to avoid swapping I'd suggest tuning your database
> first with swap turned off and put it under a "normal" load while
> watching both top and vmstat. When you're happy with it, turn swap
> back on for those "heavy" load times and move on.
>
> Greg
>
> --
> Greg Spiegelberg
> Product Development Manager
> Cranel, Incorporated.
> Phone: 614.318.4314
> Fax: 614.431.8388
> Email: gspiegelberg(at)cranel(dot)com
> Technology. Integrity. Focus.
>
>
>
>