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Re: both 8 hour 200 vu tests end in a server abort

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RW wrote:
| Hi!
| Maybe it would help a little bit if I include my config's in this
| discussion since
| I have had the same problems as Trevor shortly. So here an extract of the
| relevant settings in DB_CONFIG I'm experimenting with:
| set_cachesize     0       524288000       0
| set_lg_regionmax  1048576
| set_lg_max        104857600
| set_lg_bsize      2097152
| set_tx_max        100
| And the slapd.conf:
| cachesize         10000
| checkpoint        512     1

You are checkpointing way too often. You really only want to ensure that
database recovery (when necessary) will not take too long, and that you
don't keepexcessive archives of log files.
- -you have checkpointed at some time interval smaller than your backup
- -you have checkpointed by size at a time that allows you to run database
recovery in a short enough time.
- -never reach 2GB of active transaction logs

My reasoning (for the setup I posted before) was that I wanted at most 2
transaction logs in use, so I ensured that checkpointing occured at <
set_lg_max (I went for set_lg_max/2) and I was running hot database
backups (for the accelerated testing) every 2 minutes, so I set the time
interval less than that (but not substantially).

If you're checkpointing every second, you're going to be killing your IO
subsystem, and probably increasing mutex contention. You don't need to
over-checkpoint, since you have the transaction logs to recover from.


- --
Buchan Milne                      Senior Support Technician
Obsidian Systems                  http://www.obsidian.co.za
B.Eng                                RHCE (803004789010797)
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