Mailing List Archive

StandAlone / Network Performance
Hi all,

Finally, I got drbd 0.6.1pre2 running on my two SMP-Boxes.
Just want to tell you about the StandAlone thing:

It happens when I put a statement "disk-size=400000" (for example) in
drbd.conf.
Then I start drbd on one node, anwering yes to make it primary. cat
/proc/drbd tells me it is connected primary/unknown
Starting drbd on the other node makes both nodes StandAlone and disk is
beeing accessed as if they sync or check something. All counters show zeros.
This state lasts obviously a long time, I don´t know wether they will
connect some time ´cause I didn´t wait for that, always aborted it after 2
hours. The underlaying Partition is 512MB of size (for testing puroses.)
Removing the disk-size entry, everything works fine and both nodes connect.

I´m impressed by the much better performance of drbd now. Another Partition
of mine ist 4GB and it does a syncall in about 15 minutes. It´s on a
scsi-disk, Fujitsu 9,1GB - 7200rpm - not the fastest one I think. Maybe that
is why it has no effect on the time if I use 100Mbit/s Fast Ethernet or
1000Mbit/s Gigabit Ethernet for drbd - the time is equal. Or, my
configuration isn´t optimized. In drbd.conf I have sync-rate=30000 and
tl-size=1024. Too high? Top sais that CPU-Time for drbd is about 4% when
syncing. Maybe I should try faster disks.

My Hardware is: 2 FSC Primergy E200 with each 2*866 PIII, ServerWorksLE,
256MB reg.SDRAM, NCR UW-SCSI160 onBoard, SCA-Backplane, Intel Pro/100
Serveradapter Onboard and Intel 1000T 64Bit PCI Adapter with Crossover-Link
between.

Sincerely
Heino Schneider
Re: StandAlone / Network Performance [ In reply to ]
* Heino Schneider / bitfarm Informationssysteme GmbH <h.schneider@bitfarm-gmbh.de> [011010 18:27]:
> Hi all,
>
> Finally, I got drbd 0.6.1pre2 running on my two SMP-Boxes.
> Just want to tell you about the StandAlone thing:
>
> It happens when I put a statement "disk-size=400000" (for example) in
> drbd.conf.

You can not give a arbitrary disk-size, it __must__ be the exact size in
KB of the smaller disk. Have a look at the syslog, there should
be a message saying "Your size hint is bogus! change it to ..."

You can use "fdisk -l"

[root@amd /root]# fdisk -l /dev/hde

Disk /dev/hde: 16 heads, 63 sectors, 79780 cylinders
Units = cylinders of 1008 * 512 bytes

Device Boot Start End Blocks Id System
/dev/hde1 1 2032 1024096+ 82 Linux swap
/dev/hde2 2033 18286 8192016 83 Linux
/dev/hde3 18287 50794 16384032 83 Linux
/dev/hde4 50795 79780 14608944 5 Extended
/dev/hde5 50795 52826 1024096+ 83 Linux
/dev/hde6 52827 54858 1024096+ 83 Linux
/dev/hde7 54859 56890 1024096+ 83 Linux
/dev/hde8 56891 58922 1024096+ 83 Linux
AAAAAAAB

hde8 is 1024096 x 1024Byte + 512Byte
AAAAAAAAAAAAAAAAAA BBBBBBB

Therefore the right number is "1024096" (in my case :).

-Philipp

> Then I start drbd on one node, anwering yes to make it primary. cat
> /proc/drbd tells me it is connected primary/unknown
> Starting drbd on the other node makes both nodes StandAlone and disk is
> beeing accessed as if they sync or check something. All counters show zeros.
> This state lasts obviously a long time, I don´t know wether they will
> connect some time ´cause I didn´t wait for that, always aborted it after 2
> hours. The underlaying Partition is 512MB of size (for testing puroses.)
> Removing the disk-size entry, everything works fine and both nodes connect.
>
> I´m impressed by the much better performance of drbd now. Another Partition
> of mine ist 4GB and it does a syncall in about 15 minutes. It´s on a
> scsi-disk, Fujitsu 9,1GB - 7200rpm - not the fastest one I think. Maybe that
> is why it has no effect on the time if I use 100Mbit/s Fast Ethernet or
> 1000Mbit/s Gigabit Ethernet for drbd - the time is equal. Or, my
> configuration isn´t optimized. In drbd.conf I have sync-rate=30000 and
> tl-size=1024. Too high? Top sais that CPU-Time for drbd is about 4% when
> syncing. Maybe I should try faster disks.
>
> My Hardware is: 2 FSC Primergy E200 with each 2*866 PIII, ServerWorksLE,
> 256MB reg.SDRAM, NCR UW-SCSI160 onBoard, SCA-Backplane, Intel Pro/100
> Serveradapter Onboard and Intel 1000T 64Bit PCI Adapter with Crossover-Link
> between.
>
> Sincerely
> Heino Schneider
>
>
>
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