[Gluster-users] Gluster-users Digest, Vol 9, Issue 66

[Evan]

I added the following to the bottom of my spec file:

volume writebehind
  type performance/write-behind
  option aggregate-size 10MB # default is 0bytes
  option flush-behind off    # default is 'off'
  subvolumes afr
end-volume

which gives me the following results when making a 10MB file
# time dd if=/dev/zero of=/tmp/disktest count=10240 bs=1024
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.173179 s, 60.5 MB/s

real    0m0.183s
user    0m0.000s
sys     0m0.204s

# time dd if=/dev/zero of=/mnt/gluster/disktest count=10240 bs=1024
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 5.50861 s, 1.9 MB/s

real    0m5.720s
user    0m0.000s
sys     0m0.060s

Although this is better than I had before is there anyway to have gluster
write the data to the localBrick and then sync/afr in the background so I
could expect to see something closer to the 60 MB/s I see when writing to
the local disk directly?

Thanks

aghavendra G <raghavendra at zresearch.com> wrote:

> above afr with afr as a subvolume
>
> On Fri, Jan 23, 2009 at 12:59 AM, Evan <_Gluster at devnada.com> wrote:
>
>> Where should I put the write-behind translator?
>> Just above afr with afr as a subvolume? Or should I put it just above my
>> localBrick volume and below afr?
>>
>>
>> Here is the output using /dev/zero:
>> # time dd if=/dev/zero of=/mnt/gluster/disktest count=1024 bs=1024
>> 1024+0 records in
>> 1024+0 records out
>> 1048576 bytes (1.0 MB) copied, 1.90119 s, 552 kB/s
>>
>> real    0m2.098s
>> user    0m0.000s
>> sys     0m0.016s
>>
>> # time dd if=/dev/zero of=/tmp/disktest count=1024 bs=1024
>> 1024+0 records in
>> 1024+0 records out
>> 1048576 bytes (1.0 MB) copied, 0.0195388 s, 53.7 MB/s
>>
>> real    0m0.026s
>> user    0m0.000s
>> sys     0m0.028s
>>
>>
>> Thanks
>>
>>
>> On Thu, Jan 22, 2009 at 12:52 PM, Anand Avati <avati at zresearch.com>wrote:
>>
>>> Do you have write-behind loaded on the client side? For IO testing,
>>> use /dev/zero instead of /dev/urandom.
>>>
>>> avati
>>>
>>> On Fri, Jan 23, 2009 at 2:14 AM, Evan <_Gluster at devnada.com> wrote:
>>> > I have a 2 node single process AFR setup with 1.544Mbps bandwidth
>>> between
>>> > the 2 nodes. When I write a 1MB file to the gluster share it seems to
>>> AFR to
>>> > the other node in real time killing my disk IO speeds on the gluster
>>> mount
>>> > point. Is there anyway to fix this? Ideally I would like to see near
>>> real
>>> > disk IO speeds from/to the local gluster mount point and let the afr
>>> play
>>> > catch up in the background as the bandwidth becomes available.
>>> >
>>> > Gluster Spec File (same on both nodes) http://pastebin.com/m58dc49d4
>>> > IO speed tests:
>>> > # time dd if=/dev/urandom of=/mnt/gluster/disktest count=1024 bs=1024
>>> > 1024+0 records in
>>> > 1024+0 records out
>>> > 1048576 bytes (1.0 MB) copied, 8.34701 s, 126 kB/s
>>> >
>>> > real    0m8.547s
>>> > user    0m0.000s
>>> > sys     0m0.372s
>>> >
>>> > # time dd if=/dev/urandom of=/tmp/disktest count=1024 bs=1024
>>> > 1024+0 records in
>>> > 1024+0 records out
>>> > 1048576 bytes (1.0 MB) copied, 0.253865 s, 4.1 MB/s
>>> >
>>> > real    0m0.259s
>>> > user    0m0.000s
>>> > sys     0m0.284s
>>> >
>>> >
>>> > Thanks
>>> >
>>> > _______________________________________________
>>> > Gluster-users mailing list
>>> > Gluster-users at gluster.org
>>> > http://zresearch.com/cgi-bin/mailman/listinfo/gluster-users
>>> >
>>> >
>>>
>>
>>
>> _______________________________________________
>> Gluster-users mailing list
>> Gluster-users at gluster.org
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>>
>>
>
>
> --
> Raghavendra G
>
>
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