Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Sorry for the aside on this, but this info might be helpful for anyone who is using SLES10 SP2 and testing performance using /dev/zero. I have noticed extreme drops in output from /dev/zero on any SP2 kernel. This has actually been confirmed by Novell support... Evidently the SLES programmers in Germany changed some of the properties of /dev/zero to fix "other memory issues". According to them, /dev/zero is no longer a good measurement of throughput. Supposedly, the programmers are looking into restoring /dev/zero output performance levels, but their comment was "no one uses /dev/zero for REAL performance testing these days". Here is a good example: On a HP DL365 with 32GB of RAM, the following test: ( dd if=/dev/zero of=/dev/null bs=1G count=1 ) produced an output of 28GB/sec on SP1 and 700MB/sec on SP2. I also noticed performance differences on output to raid hardware, but don't have those numbers. Andrew Armstrong >>> On 10/20/2008 at 6:33 AM, in message <20081020103350.GA10572 at soda.linbit>, Lars Ellenberg <lars.ellenberg at linbit.com> wrote: On Sat, Oct 18, 2008 at 09:18:33PM +0200, Petersen, Joerg wrote: > Well, my experience is that 8.0.7 is the fastest DRDB... > Later Versions just got slower! > Try: no-disk-flushes > and: no-md-flushes > if you are using DRBD >= 8.0.13 > Not completely same to 8.0.7 but near to it... to recommend a known buggy version for imagined performance reasons is not particular HA. > Hi Lars, > > I did these: > > node1:/opt # hdparm -t /dev/drbd0 > Do these tests make any sence? if you care for write performance, why are you doing read benchmarks? -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed _______________________________________________ drbd-user mailing list drbd-user at lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20081020/8408c896/attachment.htm>