[DRBD-user] Performance Problem

Jeronimo Zucco jczucco at ucs.br
Mon Mar 19 01:57:41 CET 2007

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


   May be you can increase the rate value of syncer, instead 50M, try 700M. Also
what is the result of command "netstat -i" ?  Your device TX or RX is without
errors ?


--
Jeronimo Zucco
LPIC-1 Linux Professional Institute Certified
Núcleo de Processamento de Dados
Universidade de Caxias do Sul

http://jczucco.blogspot.com


Citando Ralf Schenk <rs at databay.de>:

> Hello !
>
> I've a performance problem running drbd 8.0.1 on a XEN Domain-0 (XEN
> 3.0.4-1, Kernel 2.6.16.33 all built from source, Distribution is Ubuntu
> Dapper Server).
>
> DRBD is working, but it's dead slow.
>
> The network is a Gigabit crosslink cabled Network (Intel onboard PCIe
> E1000 Card). The servers are 2x DualXEON 5130 machines (Supermicro). The
> storage System is a 3Ware 9550SX Controller with 3 500GB Seagate SATA
> HDD's as RAID 5. I optimized Controller performance by setting some
> settings /sys/block/sda/queue/XXX as advised by 3Ware and I found one
> comment from one of the DRBD Authors to set "echo 1024 >
> /sys/block/sda/queue/nr_requests" because of the queue depth of the
> 3Ware driver/controller. I also tested with standard settings.
>
> The network interface shows a performance of about 985 Mbit throughput
> measured with iperf. For low CPU usage I set the interfaces to MTU 9000
> (Jumbo frames) but I also tested with MTU of 1500.
>
> Speed on LVM Volume:
> dm -a 0 -o /dev/mb01a/shared -b 1M -s 3g -m -y -p
> 64.03 MB/sec (3221225472 B / 00:47.977005)
>
> Speed on DRBD Device built on above Volume in _disconnected_ mode:
> dm -a 0 -o /dev/drbd2 -b 1M -s 3g -m -y -p
> 34.95 MB/sec (3221225472 B / 01:27.886889)
>
> Thats already disappointing (I hoped to get 75% of the native
> performance out of the drbd device and my network connection could take
> that easily).
>
> Thats what I get in connected mode on the primary
> dm -a 0 -o /dev/drbd2 -b 1M -s 3g -m -y -p
> 2.66 MB/sec (3221225472 B / 19:13.836492)
>
> Thats hard. Are there any experiences out there like this. I think I
> have a problem in my I/O subsystem perhaps related to the combo XEN/DRBD.
>
> All tests were done in a minimal Domain-0 limited to 768 MB memory and
> no other Domains or prcesses running exept a SSH server.
>
> I already tried a bunch of max-buffer/snd-bufffer/unplug watermark etc.
> settings but I couldn't increase the data transfer rate above 5-6
> MB/sec. Also I tried the setting use-bmbv in the disk section which
> didn't help.
>
> This is the latest config:
> resource "shared" {
>   protocol C;
>   startup {
>     wfc-timeout         0;  ## Infinite!
>     degr-wfc-timeout  120;  ## 2 minutes.
>   }
>   disk {
>     on-io-error detach;
>     use-bmbv;
>   }
>   net {
>     # allow-two-primaries;
>     cram-hmac-alg sha1;
>     shared-secret "EV8CbHPLwzIW";
>     # timeout           60;
>     # connect-int       10;
>     # ping-int          10;
>     # sndbuf-size         1M;
>     max-buffers         8192;
>     max-epoch-size      1024;
>     # unplug-watermark 32768;
>   }
>   syncer {
>     rate 50M;
>     al-extents 257;
>   }
>
>   on megabad01a {
>     device      /dev/drbd2;
>     disk        /dev/mb01a/shared;
>     address     10.10.10.1:7791;
>     meta-disk   /dev/mb01a/drbd[2];
>   }
>
>   on megabad01b {
>     device      /dev/drbd2;
>     disk        /dev/mb01b/shared;
>     address     10.10.10.2:7791;
>     meta-disk   /dev/mb01b/drbd[2];
>   }
> }
>
> Bye
> --
> __________________________________________________
>
> Ralf Schenk
> fon (02 41) 9 91 21-0
> fax (02 41) 9 91 21-59
> rs at databay.de
> __________________________________________________
>
> _______________________________________________
> drbd-user mailing list
> drbd-user at lists.linbit.com
> http://lists.linbit.com/mailman/listinfo/drbd-user
>


----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.




More information about the drbd-user mailing list