[DRBD-user] CLVM over DRBD speed test

Federico Simoncelli federico.simoncelli at gmail.com
Thu Jul 2 14:37:21 CEST 2009

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


On Thu, Jul 2, 2009 at 10:39 AM, Florian Haas<florian.haas at linbit.com> wrote:
> Federico,
>
> out of curiosity: does this throughput drop also occur when you activate
> your "TestGroup00" VG in exclusive mode?

Hi Florian,
I did the tests again using just LVM:

# pvcreate /dev/cciss/c0d0p1
# vgcreate -cn TestGroup00 /dev/cciss/c0d0p1
# lvcreate -n TestSpeed00 -L 4G TestGroup00
# sync && dd if=/dev/zero of=/dev/TestGroup00/TestSpeed00 bs=1M
count=100 oflag=direct
104857600 bytes (105 MB) copied, 1,45695 seconds, 72,0 MB/s
# pvs
  PV                VG          Fmt  Attr PSize   PFree
  /dev/cciss/c0d0p1 TestGroup00 lvm2 a-   465,73G 461,73G


# sync && dd if=/dev/zero of=/dev/drbd1 bs=1M count=100 oflag=direct
104857600 bytes (105 MB) copied, 1,7703 seconds, 59,2 MB/s


# pvcreate /dev/drbd1
# vgcreate -cn TestGroup00 /dev/drbd1
# lvcreate -n TestSpeed00 -L 4G TestGroup00
# sync && dd if=/dev/zero of=/dev/TestGroup00/TestSpeed00 bs=1M
count=100 oflag=direct
104857600 bytes (105 MB) copied, 7,3782 seconds, 14,2 MB/s
# pvs
  PV         VG          Fmt  Attr PSize   PFree
  /dev/drbd1 TestGroup00 lvm2 a-   465,71G 461,71G


Do you think there might be a block alignment issue?

-- 
Federico.



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