Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 01/26/2009 12:28 PM, Mark Watts wrote: > On Friday 23 January 2009 18:13:55 Florian Haas wrote: >> Mark, >> >> On 01/23/2009 05:01 PM, Mark Watts wrote: >>> The following test was used to obtain a write average: >>> # for loop in `seq 1 10`; do echo "Writing to /empty, loop $loop"; dd >>> if=/dev/zero of=/empty bs=$(( 1024 * 1024 * 1024 )) count=4; done >> You're not writing to your disk, but to your page/buffer cache. Add >> "oflag=direct". > > Ok. We've realised that we don't have the controller batteries either, so > we're going to get some and re-test. If that is the case, it may well be that your controller is disabling its write cache unless a battery is present (all sane controllers ought to have that behaviour). That would mean you are writing in write-through mode all along. So assuming that with "oflag=direct" your write throughput is way less than you expect, that may be a possible reason. > Yep, GigE here. Having said that, if everything else is capable/tuned of going > faster then we should be hitting 100M almost all the time, right? For direct streaming writes, yes. 100 to 105MB/s should be nothing out of the ordinary. >> These resources may provide additional insights: >> http://www.linbit.com/en/education/on-demand-webinars/drbd-performance-tuni >> ng/ http://www.drbd.org/users-guide/s-configure-syncer-rate.html > > Looks like I've found my lunch-time reading :) Have fun. :-) Cheers, Florian -- When replying, there is no need to CC my personal address. I monitor the list on a daily basis. Thank you. LINBIT® and DRBD® are registered trademarks of LINBIT.