[sheepdog] Redundancy policy via iSCSI

[Hitoshi Mitake]

At Sat, 7 Feb 2015 10:03:18 +0800,
hujianyang wrote:
> 
> On 2015/2/6 16:41, Hitoshi Mitake wrote:
> > At Wed, 04 Feb 2015 11:24:21 +0900,
> > Hitoshi Mitake wrote:
> >>
> >> At Tue, 3 Feb 2015 17:17:42 +0800,
> >> hujianyang wrote:
> >>>
> >>> Hi Saeki,
> >>>
> >>> On 2015/2/3 16:53, Saeki Masaki wrote:
> >>>> Hi Hu,
> >>>>
> >>>> Since Sheepdog has a mechanism that does not place objects in the same zone_id.
> >>>> Can you try to change ZONE id in each node.
> >>>>>>>    Id   Host:Port         V-Nodes       Zone
> >>>>>>>     0   130.1.0.147:7000        128          0
> >>>>>>>     1   130.1.0.148:7000        128          0
> >>>>>>>     2   130.1.0.149:7000        128          0
> >>>>
> >>>> Best Regards, Saeki.
> >>>>
> >>>
> >>> Good suggestions~!
> >>>
> >>> Seems OK now. But write performance is too slow in my environment.
> >>
> >> 1.1MB/s seems to be too slow, how about changing input file from
> >> /dev/random to /dev/zero? And I'd like to know perofrmance of default
> >> backing store of tgt (use file as iSCSI target) on your environment.
> >>
> >> Thanks,
> >> Hitoshi
> > 
> > BTW, I have pending patchset for parallelizing iSCSI PDU send/recv of
> > tgtd:
> > https://github.com/mitake/tgt/commits/iscsi-pdu-rxtx-mt
> > 
> > You can activate the feature with new option -T:
> > $ tgtd -T 16
> > 
> > It is still half-baked, but in some cases it can improve performance
> > of iSCSI + sheepdog.
> > 
> > Thanks,
> > Hitoshi
> > 
> 
> Hi Hitoshi,
> 
> Sorry for reply late. You know, there always many stuffs need to
> been done before Spring Festival.
> 
> Actually my current environment is just for testing the features
> of sheepdog. Performance is not a urgent issue. Thanks for your
> kindness.
> 
> I have tested sheepdog with fio on my testing environment:
> 
> [global]
> runtime=300
> direct=1
> iodepth=1
> bs=256K
> size=100G
> numjobs=1
> time_based
> 
> KB/s			read	randread	write	randwrite
> local			179957	36262		179933	66752
> iSCSI	redundancy(3x)	51553	51303		17826	15984
> 	redundancy(4:2)	43166	42775		20370	14234
> SBD	redundancy(3x)	51112	51106		17515	20311
> 
> 
> I'm not quite sure why randwrite is better than randread via local
> access.

Hmm, seems odd. But thanks for your report.

BTW, I'm preparing LTTng tracepoints in sheepdog. It is still ongoing
but it will useful for analyzing performance of sheepdog. If you know
LTTng, please try it :)

Thanks,
Hitoshi

> 
> Thanks,
> Hu
> 
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