[DRBD-user] Performance issue

Sampo Blom sampo.blom at vsp.fi
Tue Aug 12 14:46:00 CEST 2008

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

Network between two boxes carried data prox. 110MB/s, so I took sync
rate 33M (110 x 0,3 = 33M).

        Command line used: iozone -s 262144 -f /data/export/test
        Output is in Kbytes/sec
        Time Resolution = 0.000001 seconds.
        Processor cache size set to 1024 Kbytes.
        Processor cache line size set to 32 bytes.
        File stride size set to 17 * record size.
random    bkwd  record  stride
              KB  reclen   write rewrite    read    reread    read
write    read rewrite    read   fwrite frewrite   fread  freread
          262144       4  401183  529283  3022257  2880264 2431338
1035372 2778243 1177529 2508961   407557   608464 3008315  2866530

iozone test complete.


-----Original Message-----
From: Maciej Bogucki [mailto:macbogucki at gmail.com] 
Sent: 12. elokuuta 2008 17:13
To: Sampo Blom
Cc: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] Performance issue

Sampo Blom wrote:
> I have two:
> Intel Q6600 boxes with 4GB of RAM
> 8 x 750Gb (4,5TB RAID5EE, Adaptec 2820SA)
> 2 x 1Gbit Ethernet
> eth0: LAN
> eth1: DRBD SYNC (crosscable between machines)
> /dev/sda2 ~4,5TB for DRBD
> The problem is that, when I connect to an ftp/samba server on LAN 
> (eth0) and I start uploading a file. Transfer rate is about 20-40MB/s 
> about 10-15 seconds, then it starts lagging, about 4-10MB/s. 
> Transfer-rate sleeps 0MB/s 5 seconds for example and all ftp transfers

> gets timeout.
> I have monitored eth1 with iptraf, and it doesn't sync more that 
> 6-10MB/s while drbd state is (cs:Connected st:Primary/Secondary 
> ds:UpToDate/UpToDate C r---).
> When drbd does sync while other end has been offline for a while...
> rate is about 20-25MB/s.

1. Test You network between the two boxes with fe. netperf
2. Test disc read/write speed with fe. bonnie++

Best Regards
Maciej Bogucki

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