[DRBD-user] Slow syncall after kernel+drbd upgrade

Christian Hammers ch at westend.com
Wed Jan 21 06:58:15 CET 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hello

On Tue, Jan 20, 2004 at 12:51:28PM +0100, Lars Ellenberg wrote:
> > I used to have 2.4.23 and drbd 0.6.4 running on two servers sharing
> > 2x 5GB over a 100MBit crosslink.
> > 
> > Now I upgraded to 2.4.24 and drbd 0.6.10 and two Intel e1000.o gigabit
> > cards and my syncall time drops from about 15mins to more than 1h!
> >
> > After the syncinc was done, I tested the link with "rsync -v -a
> > --progress ..." and got at least 15MB/s = 120MBit/s which is not much 
> > for a 1000MBit/s link but at least more than 2MBit/s that drbd got!
> > 
> > Below you find the "cat /proc/drbd" and the "drbdsetup /dev/nb0 show" 
> > outputs. The sync-max values differ a bit as I played around before
> > giving up...

...
> >  sync-min = 200 KB/sec
> you should increase sync-min !!
> >  sync-max = 5000 KB/sec
> of course you want to increase sync-max again...
> >  sync-nice = 10
> you should probably sync-nice = -10 or so

And so I did. I also changed the devices MTU size to 5000 and verified
with iptraf that this large packet size is actually used. It is.
I could rsync a 100MB file over the very same crossover cable with
15MB/s and the servers are quite idle according to vmstat :-(

But the syncAll still is no bit faster!

bye,

-christian-

root at mail3b:~# cat /proc/drbd 
version: 0.6.10 (api:64/proto:62)

0: cs:SyncingAll st:Secondary/Primary ns:0 nr:1435652 dw:1435652 dr:0 pe:0 ua:15
        [=====>..............] sync'ed: 26.8% (3668/5004)M
        finish: 0:47:57h speed: 1,319 (1,313) K/sec
1: cs:SyncingAll st:Secondary/Primary ns:0 nr:1367248 dw:1367248 dr:0 pe:0 ua:15
        [=====>..............] sync'ed: 26.7% (3672/5004)M
        finish: 0:47:40h speed: 1,336 (1,310) K/sec

root at mail3a:~# drbdsetup /dev/nb0 show	<--- same value on both hosts
Lower device: 08:07   (/dev/sda7)            and both partitions.
Disk options:
 disk-size = 5124703 KB
 do-panic
Local address: 10.10.10.1:7788
Remote address: 10.10.10.2:7788
Wire protocol: C
Net options:
 timeout = 6.0 sec
 tl-size = 5000
 connect-int = 10 sec
 ping-int = 10 sec
 sndbuf-size = 131070
 sync-min = 100000 KB/sec
 sync-max = 122070 KB/sec
 sync-nice = -10



-- 
Christian Hammers             WESTEND GmbH  |  Internet-Business-Provider
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