Hi guys,

Ulrich - thanks for the suggestions - btrfs in particular is certainly worth a shot.

Quanah - very cool to hear about the 12.04 kernel and ext2 suggestions. thanks!

I've just run some new tests on a similar machine with 12.04.4 LTS and a newly installed 3.11.0-15-generic x86_64 kernel.

Exact same testing method as before, 10K records, etc:

Running on an ext4 partition:

Base-line, no extra options: 5m14s
With "writemap" enabled: 9m40s
With "writemap+mapasync" enabled: 4m35s

Overall, about the same as 10.04 for me.

I created a new ext2 partition to give that a shot on the 12.04 box.

Base-line, no extra options: 1m31s 
With "writemap" enabled: 1m33s
With "writemap+mapasync" enabled: 1m41s

Ahah! I'd say that's the killer answer.

Summary for future generations who may see this thread:

1) Using ext2 for your db directory (on Ubuntu at least) is waay faster than ext4 (~2-3x as fast according to my tests). This is the secret as far as I'm concerned since you can use this while still using the most conservative DB options that don't risk your data.
2) Using "dbnosync+checkpoint" with mdb is the absolute fastest method, but at the cost of risking data loss 

Cheers,
Andrew


On Thu, Feb 6, 2014 at 5:08 AM, Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> wrote:
>>> Andrew Eross <eross@locatrix.com> schrieb am 05.02.2014 um 16:30 in Nachricht
<CAL_tfFf2qW5BcT=Xs4uFOSUO=wL0AN=9CyfS+D-XYPLitMZ_aw@mail.gmail.com>:
> Hi Quanah,
>
> Ubuntu 10.04 LTS
> Linux 2.6.32-43-generic-pae #97-Ubuntu SMP Wed Sep 5 16:59:17 UTC 2012 i686
> GNU/Linux
> The latest OpenLDAP 2.4.39
> All of those tests done with the mdb backend, of course, and the actual
> file system is ext4

Did you try btrfs? I'd guess it could be faster for massive random writes.

>
> It's a fairly stock 10.04 system, no special config/kernel changes.
>
> Cheers,
> Andrew
>
> On Wed, Feb 5, 2014 at 1:26 PM, Quanah Gibson-Mount <quanah@zimbra.com>wrote:
>
>> --On Tuesday, February 04, 2014 6:52 PM -0200 Andrew Eross <
>> eross@locatrix.com> wrote:
>>
>>
>>>
>>> Thanks, Dieter, Quanah.
>>>
>>>
>>> I've been doing some experimenting with those mdb options.
>>>
>>>
>>> I ran a few tests with inserting 10,000 records, wiping the DB in
>>> between, and changing just the one option at a time:
>>>
>>>
>>> Base-line, no extra options: 4m8sWith "writemap" enabled: 8m55s
>>>
>>> With "writemap+mapasync" enabled: 5m12s
>>> With "dbnosync+checkpoint 0kb/1min": 0m14s
>>>
>>
>> I know you answered some of this before, but please update with:
>>
>> What kernel?
>> What OpenLDAP version?
>> What Ubuntu release?
>> What filesystem for the LDAP DB?
>>
>> Thanks,
>>
>> Quanah
>>
>>
>> --
>>
>> Quanah Gibson-Mount
>> Architect - Server
>> Zimbra, Inc.
>> --------------------
>> Zimbra ::  the leader in open source messaging and collaboration
>>