Thanks, Ulrich. That made me do a bit searching, there's a nice summary of some of the ext4 performance options here: http://blog.smartlogicsolutions.com/2009/06/04/mount-options-to-improve-ext4-file-system-performance/
Definitely cool ideas (but more academic for us specifically) - I'd be a bit nervous to use those options in our XenServer (with local disks) VM environment, when looking to only gain some %s in ext4 performance. Andrew Eross CTO Locatrix Communications Office: +61 7 3123 1469 Mobile: +55 37 9858 9815 [email protected] On Fri, Feb 7, 2014 at 5:21 AM, Ulrich Windl < [email protected]> wrote: > Hi! > > Another suggestion: Dependingon your secondary storage you could > experiment with mount option barrier=0: If you have a RAID controller with > battery backed-up cache (that guarantees that any data confirmed "written" > to the host will acually be written in the end) it makes no sense to force > the controller to flush the cache before the host may continue. Especially > if you have big shared SAN storage system... > > For plain local disks you are putting data integrity at risc, especially > for journaled filesystems in you skip barrieres. Still if you plan a > repeatable initial database load, you could disable barriers temporarily. > In case of a system crash, you probably have to re-load all your data... > > Ulrich > > >>> Andrew Eross <[email protected]> schrieb am 06.02.2014 um 16:59 in > Nachricht > <cal_tffds4sukqn7zfskfgq1re7qehsyygos0rqv_ow71j_r...@mail.gmail.com>: > > 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 < > > [email protected]> wrote: > > > >> >>> Andrew Eross <[email protected]> schrieb am 05.02.2014 um 16:30 in > >> Nachricht > >> <CAL_tfFf2qW5BcT=Xs4uFOSUO=wL0AN=9cyfs+d-xyplitmz...@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 < > [email protected] > >> >wrote: > >> > > >> >> --On Tuesday, February 04, 2014 6:52 PM -0200 Andrew Eross < > >> >> [email protected]> 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 > >> >> > >> > >> > >> > >> > > >
