[DRBD-user] DRBD performance and heavy load

Mario Peschel mario at uni.de
Sun Mar 9 21:58:14 CET 2008

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


Hi Sam,

I tried the newest kernel 2.6.24 with the kernel module mptsas, without 
any success.

Then I found the following solution:

http://lists.us.dell.com/pipermail/linux-precision/2007-June/001188.html

Now my performance is much better:

# dd if=/dev/zero bs=4096 count=10000 of=/tmp/testfile oflag=dsync
10000+0 records in
10000+0 records out
40960000 bytes (41 MB) copied, 7.02387 seconds, 5.8 MB/s

Mario

Sam schrieb:
> Mario,
> 
> Your results are similar to ours. I have not yet found a solution to
> improve the 5iR controller's performance. I believe there is a newer
> version of the driver available, but I have not attempted to install
> it yet. I will keep you informed of any progress and ask you to do the
> same.
> 
> Thanks,
> 
> Sam
> 
> On Sun, Mar 2, 2008 at 3:27 PM, Mario Peschel <mario at uni.de> wrote:
>> Hi Sam,
>>
>>  this is the result of our dd:
>>
>>  # dd if=/dev/zero bs=4096 count=10000 of=/tmp/testfile oflag=dsync
>>  10000+0 records in
>>  10000+0 records out
>>  40960000 bytes (41 MB) copied, 263.415 seconds, 155 kB/s
>>
>>  Very slow. :-( But it shows that drbd is not the cause for this poor
>>  performance.
>>
>>  We also got two new Dell R200 servers with the newer SAS 6iR RAID
>>  controller, this are the results:
>>
>>  # dd if=/dev/zero bs=4096 count=10000 of=/tmp/testfile oflag=dsync
>>  10000+0 records in
>>  10000+0 records out
>>  40960000 bytes (41 MB) copied, 8.22052 seconds, 5.0 MB/s
>>
>>  Looks like the newer controller is working better with Linux.
>>
>>  But do you have any idea to get the 5iR controller working a bit faster?
>>
>>  Mario
>>
>>  Sam schrieb:
>>
>>
>>> Hi Mario,
>>  >
>>  > I think the problem might be with the SAS 5iR. I see similarly poor
>>  > performance for small writes on a Dell SC1435 with the same
>>  > controller.
>>  >
>>  > Try the following test and let me know your result:
>>  >
>>  > dd if=/dev/zero bs=4096 count=10000 of=/some/file/on/your/raid/disk oflag=dsync
>>  >
>>  > Sam
>>  >
>>  > On Fri, Feb 29, 2008 at 1:22 AM, Mario Peschel <mario at uni.de> wrote:
>>  >> Hello,
>>  >>
>>  >>  we have two brand new Dell Server PE860 Quad-Core Xeon X3220 2.4GHz with
>>  >>  4GB memory, 2x250 GB SATA HDD and SAS 5iR RAID controller running RAID1
>>  >>  each. Both servers are connected with a gigabit crossover cable for DRBD
>>  >>  replication.
>>  >>
>>  >>  We're using Debian Linux with kernel 2.6.18-fza-5-amd64 (for use with
>>  >>  OpenVZ) drbd 8.2.4.
>>  >>
>>  >>  We noticed a heavy load when running some performance tests with bonnie++:
>>  >>
>>  >>  rod:/root# bonnie++ -d /vz/tmp -u 1000
>>  >>  Using uid:1000, gid:1000.
>>  >>  Writing with putc()...done
>>  >>  Writing intelligently...done
>>  >>  Rewriting...done
>>  >>  Reading with getc()...done
>>  >>  Reading intelligently...done
>>  >>  start 'em...done...done...done...
>>  >>  Create files in sequential order...done.
>>  >>  Stat files in sequential order...done.
>>  >>  Delete files in sequential order...done.
>>  >>  Create files in random order...done.
>>  >>  Stat files in random order...done.
>>  >>  Delete files in random order...done.
>>  >>  Version  1.03       ------Sequential Output------ --Sequential Input-
>>  >>  --Random-
>>  >>                      -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
>>  >>  --Seeks--
>>  >>  Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
>>  >>  /sec %CP
>>  >>  rod              8G  1790   2  4477   1  5257   1 65267  83 63655   7
>>  >>  151.5   0
>>  >>                      ------Sequential Create------ --------Random
>>  >>  Create--------
>>  >>                      -Create-- --Read--- -Delete-- -Create-- --Read---
>>  >>  -Delete--
>>  >>                files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
>>  >>  /sec %CP
>>  >>                   16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
>>  >>  +++++ +++
>>  >>  rod,8G,1790,2,4477,1,5257,1,65267,83,63655,7,151.5,0,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++
>>  >>
>>  >>  Our configuration (drbd.conf) on both servers:
>>  >>
>>  >>  global {
>>  >>    usage-count yes;
>>  >>  }
>>  >>  common {
>>  >>    syncer { rate 40M; }
>>  >>  }
>>  >>  resource r0 {
>>  >>    protocol C;
>>  >>    handlers {
>>  >>      pri-on-incon-degr "echo o > /proc/sysrq-trigger ; halt -f";
>>  >>      pri-lost-after-sb "echo o > /proc/sysrq-trigger ; halt -f";
>>  >>      local-io-error "echo o > /proc/sysrq-trigger ; halt -f";
>>  >>      outdate-peer "/usr/lib/heartbeat/drbd-peer-outdater -t 5";
>>  >>    }
>>  >>    startup {
>>  >>      degr-wfc-timeout 120;
>>  >>    }
>>  >>    disk {
>>  >>      on-io-error   detach;
>>  >>    }
>>  >>    net {
>>  >>      after-sb-0pri disconnect;
>>  >>      after-sb-1pri disconnect;
>>  >>      after-sb-2pri disconnect;
>>  >>      rr-conflict disconnect;
>>  >>    }
>>  >>    syncer {
>>  >>      rate 40M;
>>  >>      al-extents 257;
>>  >>    }
>>  >>    on rod {
>>  >>      device     /dev/drbd0;
>>  >>      disk       /dev/sda3;
>>  >>      address    192.168.1.2:7788;
>>  >>      meta-disk  internal;
>>  >>    }
>>  >>    on todd {
>>  >>      device    /dev/drbd0;
>>  >>      disk      /dev/sda3;
>>  >>      address   192.168.1.1:7788;
>>  >>      meta-disk internal;
>>  >>    }
>>  >>  }
>>  >>
>>  >>  This is very slow. Anyone have an idea why it is so or what we can try
>>  >>  to boost up the performance?
>>  >>
>>  >>  Thanks,
>>  >>
>>  >>  Mario
>>  >>  _______________________________________________
>>  >>  drbd-user mailing list
>>  >>  drbd-user at lists.linbit.com
>>  >>  http://lists.linbit.com/mailman/listinfo/drbd-user
>>  >>
>>
>>




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