Re: Testing write master and multiple read clients on NFS share

[Michael Weinrich <micxer@micxer.de>]

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Thanks for the hint. I also found another mistake in limiting the reads 
and writes where I only wanted to limit the writes and have the reads as 
fast as possible. But in general this is a viable approach to my problem?

Am 16.05.15 um 13:46 schrieb Sitsofe Wheeler:
> On 14 May 2015 at 23:09, Michael Weinrich <micxer@micxer.de> wrote:
>> Hi,
>>
>> in my company we have some sort of database that operates on bit lists read
>> directly from the files on the hard disk. While this is ok if you have an
>> SSD in your server it gets tricky to keep performance up when using an NFS
>> share.
>>
>> While I was trying to assess different solutions I stumbled upon fio and was
>> happy to see that it can also run in client-server-mode. So I was trying to
>> emulate the following scenario:
>>
>> - 1 node that takes care of updating the bit lists in the db files,
>>    nothing else
>> - 5 nodes that only read from those files and respond to queries, hopefully
>> leveraging the local filesystem or NFS client cache
>>
>> I read through the HOWTO and tried to pick the options that should simulate
>> the scenario as best as possible. This is what I came up with:
>>
>> [global]
>> ioengine=sync
>> iodepth=1
>> size=100%
>> io_size=4g
>> filesize=4g
>> blocksize=64k
>> direct=0
>> numjobs=4
>> directory=/mnt/nfs
>> filename_format=index.$filenum
>> fadvise_hint=0
>> lockfile=readwrite
>> randrepeat=1
>> nrfiles=8
>> openfiles=4
>> runtime=120
>> ramp_time=10
>> blocksize=64k
>> file_service_type=random:8
>> overwrite=1
>> fsync_on_close=1
>> random_distribution=zipf:0.6
>> norandommap
>> file_append=0
>> rate=1m
>>
>> [reader]
>> rw=randread
>>
>> [writer]
>> rw=randrw
>> rwmixwrite=80
>>
>>
>> Is this a viable approach or is this scenario not really testable with fio?
>
> I could be wrong but won't this make 4 readers and 4 writers. If
> that's not what you wanted perhaps numjobs could be moved to the
> reader entry only?
>


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