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From Pranav Desai <pranavade...@gmail.com>
Subject Re: Need some help tuning for large file performance
Date Fri, 17 Sep 2010 16:41:06 GMT
On Fri, Sep 17, 2010 at 7:35 AM, John Plevyak <jplevyak@apache.org> wrote:
> I just added a new option (and default) for large files to
> the SVN repository.   This dramatically improves performance
> of large files, particularly on configurations with fewer
> disks.

What is the option ?

>
> I have tried to repro the crash issue with large files and
> large ram disk to no avail.
>
> If you could try out the SVN version and make available
> your testing procedure so that I can reproduce the issue
> it would really help to get a fix.
>

I will try with the 2.1.2 version again to recheck if I screwed up
something and see if I can reproduce it with the SVN version.

I will create and update a thread for this issue on the dev list.

-- Pranav

> john
>
> On 9/16/2010 7:57 PM, Leif Hedstrom wrote:
>>  On 09/16/2010 08:09 PM, Pranav Desai wrote:
>>> On
>>> Done. Using 2 disks. Do you recommend a raid config for better
>>> performance ?
>>
>> No, I recommend RAID only if you really, really care for redundancy /
>> reliability. ATS will automatically "load balance" across any disks that
>> you throw at it.
>>
>>>
>>> Here are my tcp mem parameters. And req/sec isnt of concern here so I
>>> should be ok with the listen queue and backlogs. If you have any
>>> particular setting in mind please let me know.
>>>
>>> net.ipv4.tcp_mem = 1339776      1786368 2679552
>>> net.ipv4.tcp_wmem = 4096        87380   8388608
>>> net.ipv4.tcp_rmem = 4096        87380   8388608
>>
>> These would only make a difference if there's a latency between the
>> client and the server (which is generally not the case in a "lab").  The
>> above are for the autoscaling window sizes I think, which seem
>> reasonable. There are settings in records.config to bump up the initial
>> window size for the connections:
>>
>> CONFIG proxy.config.net.sock_send_buffer_size_in INT 262144
>> CONFIG proxy.config.net.sock_recv_buffer_size_in INT 0
>> CONFIG proxy.config.net.sock_send_buffer_size_out INT 0
>> CONFIG proxy.config.net.sock_recv_buffer_size_out INT 0
>>
>>
>> You definitely want to tune that mmap setting I mentioned earlier, and a
>> few other interesting sysctl's would be
>>
>>     net.ipv4.tcp_max_syn_backlog (set it pretty high)
>>     net.core.somaxconn
>>     net.ipv4.tcp_syncookies (enable it)
>>     net.ipv4.ip_local_port_range
>>     net.ipv4.tcp_ecn (probably want it disabled)
>>     net.ipv4.tcp_max_tw_buckets (increase for lots of sockets I think)
>>
>>
>>>
>>> I think I can reproduce it but under load, so it might be a bit
>>> difficult to debug it especially with all the threads. I will try to
>>> get to a simpler test case to reproduce it. Maybe I can run
>>> traffic_server alone with a single network and io thread ? How do you
>>> guys normally debug it ?
>>
>>
>> I think we should move the discussions related to this crasher problem
>> to the dev@trafficserver.apache.org mailing list (information how to
>> subscribe to it is on http://trafficserver.apache.org). There's a wider
>> crowd there that might be able to help as well, in particular John
>> Plevyak knows the cache better than anyone else on the planet.
>>
>> That much said, if you can reproduce it with restrictions like you
>> mention, that'll certainly help. Or, just describe how to setup the
>> environment, and what "load" to send to it, that might also help. But
>> the more you can limit the parameters / tests / time necessary to
>> reproduce it, the better.
>>
>> Thanks!
>>
>> -- leif
>
>

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