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@cranel.com>
To: <stange@rentec.com>
Cc: "Kevin Schroeder" <kschroeder@mirageworks.com>;
<pgsql-performance@postgresql.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@cranel.com
> Technology. Integrity. Focus.
>
>
>
>