How do I increase default DBD cache size

[Ramprasad]

> No need to patch the code for that - it's an option!  Just put:
> 
> berkeley_cachesize: 4096
> 
> in your /etc/imapd.conf
> 
> We use skiplist for our mailboxes.db and we haven't seen any issues that
> were caused by leaving that at its default value.
> 

I need to compile cyrus with skiplist right ? 
What are the pros and cons of skiplist ? 




> That said:
> 
> % cat $confdir/db/DB_CONFIG
> set_cachesize 0 2097152 1
> set_lg_regionmax 2097152
> set_lg_bsize 2097152
> set_lg_max 16777216
> set_tx_max 200
> set_tas_spins 1
> % 
> 


I dont have this file in my db directory ( /var/lib/imap/db ) 
Do I have to create this file ?


> (and no, I didn't set that up, so I'm not sure why all those values.  It
> works for us though)
> 
> Sounds like your hardware should cope OK with 600 connections:
> 
> [root at imap2 root]$ netstat -n -a | grep :2143 | wc -l
> 2232
> 
> And that's at one of our least busy times.  I expect it goes up to 2 or
> 3 times that during the U.S. day.
> 
> NOTE: we're using reiserfs for our drives, and that machine has 42
> partitions split over 8 different raidsets via two separate SCSI
> controllers, and a split meta configuration that puts the meta data
> on RAID1 for speed.  Still, it's possible to get an order of magnitude
> more connections out of that sort of spec.  That's 8Gb of memory in
> that machine, and dual hyperthreading Xeons:
> 

Why do you have so many partitions ? And do you run the MTA on the same
machine ? 

Thanks
Ram



> model name      : Intel(R) Xeon(TM) CPU 2.40GHz
> stepping        : 7
> cpu MHz         : 2394.878
> 
> (there's some headroom left with the memory still too...)
> -/+ buffers/cache:    6118564    2193000
> 
> Bron.