Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Mon, Jan 12, 2009 at 03:58:17PM +0100, Lars Täuber wrote:
> Hallo you!
>
> Igor Neves <igor at 3gnt.net> schrieb:
> > Hello,
> >
> > Yes this is true. The metadata can be the problem, i would just use a
> > simple raid setup, everything over hardware raid.
>
> The metadata doesn't seem to be the problem. I hope this config puts the meta data onto a ramdisk:
> # drbdadm dump
> # /etc/drbd.conf
> common {
> protocol C;
> syncer {
> rate 1150M;
> }
> handlers {
> split-brain "/usr/lib/drbd/notify-split-brain.sh root";
> }
> }
>
> # resource RAID61 on monosan: not ignored, not stacked
> resource RAID61 {
> on monosan {
> device /dev/drbd0;
> disk /dev/md4;
> address ipv4 10.9.8.7:7788;
> flexible-meta-disk /dev/ram0;
> }
> on duosan {
> device /dev/drbd0;
> disk /dev/md4;
> address ipv4 10.9.8.6:7788;
> flexible-meta-disk /dev/ram0;
are you _sure_ that drbd uses that?
(drbdsetup /dev/drbd0 show)
you are aware that you'll get a full sync again?
> }
> disk {
try add (introduced more recently:)
no-disk-barrier;
to see if it changes something.
if it does: use at your own risk.
> no-disk-flushes;
> no-md-flushes;
> }
> }
>
> But the speed hasn't increased so far:
> # cat /proc/drbd
>
> version: 8.3.0 (api:88/proto:86-89)
> GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by root at monosan, 2009-01-09 15:15:29
> 0: cs:SyncTarget ro:Secondary/Primary ds:Inconsistent/UpToDate C r---
> ns:0 nr:22204216 dw:22201608 dr:0 al:0 bm:1352 lo:654 pe:9889 ua:652 ap:0 ep:1 wo:b oos:6530218744
> [>....................] sync'ed: 0.4% (6377166/6398848)M
> finish: 59:40:09 speed: 30,364 (88,804) K/sec
>
>
> What are the other possible bottlenecks?
md resyncing at the same time? ;)
misaligned device offset?
secondary device performance?
device latencies?
max-buffers (and max-epoch);
al-size;
your sync-rate is set _much_ too high. unit is _bytes_ not bits, we are
storage guys. and it is meant to be a _throttle_. increasing it way
beyond physical limits does hurt, not help.
--
: 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.
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