[DRBD-user] sync rate seems low

Monty Taylor mtaylor at mysql.com
Wed Aug 9 03:05:24 CEST 2006

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


I couldn't agree more! It would also be really nice to be able to
query drbd to find out what values the config settings are set to.

Monty

On 8/8/06, Vampire D <vampired at gmail.com> wrote:
> I really wish there was a interface to tell how fast the drbd devices are
> syncing.
>
>
>
> On 8/8/06, Monty Taylor <mtaylor at mysql.com> wrote:
> > When I get back in tomorrow, I'm going to do a disk benchmark as well
> > as scp'ing a big file. I wasn't showing any significant iowait on
> > either of the boxes, so I was originally not thinking it was disk -
> > but I could be wrong.
> >
> > I'll post when I know how the disk test turns out.
> >
> > Thanks,
> > Monty
> >
> > On 8/8/06, Gary W. Smith < gary at primeexalia.com> wrote:
> > > But an scp would indicate disk latency as well.  It's great they all
> > > talk 1gb but can they handle 1gb?  As Clive mentioned, try scp'ing a
> > > 100mb file and see if you are also getting 8mb/sec.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: drbd-user-bounces at lists.linbit.com
> > > [mailto: drbd-user-bounces at lists.linbit.com] On Behalf
> Of Monty Taylor
> > > Sent: Tuesday, August 08, 2006 4:12 PM
> > > To: Vampire D
> > > Cc: drbd-user at lists.linbit.com
> > > Subject: Re: [DRBD-user] sync rate seems low
> > >
> > > I agree, that's what it seems like. But then I ran iperf on the
> > > interface and got this:
> > >
> > > [  3] local 192.168.0.2 port 32810 connected with 192.168.0.1 port 5001
> > > [ ID] Interval       Transfer     Bandwidth
> > > [  3]  0.0-10.0 sec  1.08 GBytes   929 Mbits/sec
> > >
> > > Which is more like what I'd expect to see. On the interface. So why is
> > > DRBD only seeing 100M while the interface can support and is running
> > > at 1G?
> > >
> > > Thanks!
> > > Monty
> > >
> > > On 8/8/06, Vampire D <vampired at gmail.com > wrote:
> > > >
> > > > Well first off, I doubt you will be any where near 125M sync rate,
> > > that's
> > > > 125MB/s if I am not mistaken.  I run GBit connections and I only have
> > > a sync
> > > > rate of around 60M.
> > > >
> > > > 2nd, 100Mbit caps at around 12MB/s throughput and 10Mbit is roughly
> > > 1.2Mb/s
> > > > so it is definately at 100Mbit.  But 8Mbit isn't all that bad for
> > > 100Mbit,
> > > > it is only 2/3rds of the capacity of your network interface, so I
> > > assume
> > > > your disk sub system is your bottleneck one way or another.  Try
> > > benching
> > > > your drives with timed dd or use some bench tool.
> > > >
> > > > With two raptors and Gbit ethernet cross over cabled, I get around
> > > 56Mb/s
> > > > but I haven't been able to test the sync rate since the initial sync
> > > and no
> > > > one seems to have an answer to easily test that after the drbd is
> > > > consisitent.
> > > >
> > > >
> > > > On 8/8/06, Monty Taylor <mtaylor at mysql.com> wrote:
> > > > >
> > > > Hey all,
> > > >
> > > > I'm rolling out a DRBD at the moment and I'm getting much lower
> > > > initial sync rate than I would expect. I have the two machines
> > > > connected with crossover cables and the rate set at 125M, but I'm only
> > > > seeing 8M/sec of transfer rate.
> > > >
> > > > I'm sure I'm missing something stupid, but I've rolled DRBD out
> > > > several times over the past couple of months and never had this
> > > > problem. Anybody have an idea of something I can check?
> > > >
> > > > Thanks,
> > > > Monty
> > > > _______________________________________________
> > > > drbd-user mailing list
> > > > drbd-user at lists.linbit.com
> > > > http://lists.linbit.com/mailman/listinfo/drbd-user
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > > "Do the actors on Unsolved Mysteries ever get arrested because they
> > > look
> > > > just like the criminal they are playing?"
> > > >
> > > > Christopher
> > > >
> > > _______________________________________________
> > > drbd-user mailing list
> > > drbd-user at lists.linbit.com
> > > http://lists.linbit.com/mailman/listinfo/drbd-user
> > >
> > >
> >
>
>
>
> --
>
>  "Do the actors on Unsolved Mysteries ever get arrested because they look
> just like the criminal they are playing?"
>
> Christopher
>



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