DB_CONFIG

[Michael Loftis]

I highly doubt your deliver.db, mailboxes.db, and everything all combined 
are even more than 1Gb.  First rule of system tuning, don't just turn 
everythign to the max because it sounds better.  Heck under 32-bit you 
CAN'T access more than 2Gb by default anyway in cache.  Since it's a 2/2 
split.  There are patches to produce other splits, but htats the default.

--On Saturday, December 04, 2004 05:02 +0200 ocl <ocl at arayan.com> wrote:

> I am sorry, I posted too early.
>
> I think I am getting somewhere, but not quite there yet.
>
> This is the contents of /var/lib/imap/db/DB_CONFIG
>
>     set_cachesize    2 0 8
>     set_lg_regionmax 268435456
>     set_lg_bsize     67108864
>     set_flags DB_TXN_WRITE_NOSYNC
>
> IOW, I am going for
>
> -- cachesize of 2 GB in 8 buckets.
> -- regionmax of 256 MB
> -- bsize of 64 MB
>
> I have 8 GB RAM on this machine, I want to have /large/
> allowances for BDB --just to be on the safe side.
>
> Trouble is, I have no idea what /safe side/ means in this
> context.
>
> What complicates the issue more is the result of 'db_stat -m',
> which reads as below. Now, where is my 2GB cache?
>
> 259KB 896B      Total cache size (266112 bytes).
> 1       Number of caches.
> 270336  Pool individual cache size.
> 52664   Requested pages found in the cache (100%).
> 0       Requested pages mapped into the process' address space.
> 229     Requested pages not found in the cache.
> 0       Pages created in the cache.
> 229     Pages read into the cache.
> 259     Pages written from the cache to the backing file.
> 2       Clean pages forced from the cache.
> 166     Dirty pages forced from the cache.
> 0       Dirty buffers written by trickle-sync thread.
> 63      Current clean buffer count.
> 0       Current dirty buffer count.
> 67      Number of hash buckets used for page location.
> 52851   Total number of times hash chains searched for a page.
> 5       The longest hash chain searched for a page.
> 80851   Total number of hash buckets examined for page location.
> 119878  The number of region locks granted without waiting.
> 1       The number of region locks granted after waiting.
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Pool File: /var/lib/imap/tls_sessions.db
> 4096    Page size.
> 44      Requested pages found in the cache (96%).
> 0       Requested pages mapped into the process' address space.
> 2       Requested pages not found in the cache.
> 0       Pages created in the cache.
> 2       Pages read into the cache.
> 9       Pages written from the cache to the backing file.
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Pool File: /var/lib/imap/deliver.db
> 4096    Page size.
> 52620   Requested pages found in the cache (100%).
> 0       Requested pages mapped into the process' address space.
> 227     Requested pages not found in the cache.
> 0       Pages created in the cache.
> 227     Pages read into the cache.
> 250     Pages written from the cache to the backing file.
>
> Cheers,
> Ray
>
> ---
> Cyrus Home Page: http://asg.web.cmu.edu/cyrus
> Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu
> List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
>



--
Undocumented Features quote of the moment...
"It's not the one bullet with your name on it that you
have to worry about; it's the twenty thousand-odd rounds
labeled `occupant.'"
   --Murphy's Laws of Combat

---
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