Can multiple nginx instances share a single proxy cache store?

[姚伟斌]

Maybe you can try the srcache module:
https://github.com/agentzh/srcache-nginx-module.

This module can store and fetch cached page from remote memcached.

Thanks.

2012/7/31 Isaac Hailperin <i.hailperin at heinlein-support.de>:
> Thank you Maxim, I have made my decision now!
>
> Isaac
>
>
> On 07/31/2012 03:58 PM, Maxim Dounin wrote:
>>
>> Hello!
>>
>> On Tue, Jul 31, 2012 at 03:35:25PM +0200, Isaac Hailperin wrote:
>>
>>>
>>> Hi,
>>>
>>> I am planning to deploy multiple nginx servers (10) to proxy a bunch
>>> of apaches(20). The apaches host about 4000 vhosts, with a total
>>> volume of about 1TB.
>>> One scenario I am thinking of with regard to hard disk storage of
>>> the proxy cache would be to have a single storage object, eg. NAS,
>>> connected to all 10 nginx servers via fibre channel.
>>>
>>> This would have the advantage of only pulling items into cache once,
>>> and would also avoid cache inconsistencies, which could at least be
>>> a temporal problem if all 10 nginx servers would have their own
>>> cache.
>>>
>>> My question now is: would this work in theory?
>>> Can multiple nginx instances share a single proxy cache store?
>>
>>
>> No.
>>
>>> I am thinking of cache management, all 10 nginx instances would try
>>> to manage the same cache directory. I don't know enough about the
>>> cache management to understand if there are problems with this
>>> scenario.
>>>
>>> Strictly speaking this is a second question, but still: the
>>> alternative would be to give the nginx local storage for the proxy
>>> cache (e.g. a raid 5, or even jbod (just a bunch of disks)). This
>>> would obviously be much simpler to set up and manage, und thus be
>>> more robust (the single storage would be a single point of failure).
>>> Which would you recommend?
>>
>>
>> Use local storage.
>>
>> The main disadvantage of a network storage pretending to be a
>> local filesystem is blocking I/O.  Even with fully working AIO (in
>> contrast to one available under Linux, which requires directio)
>> there are still blocking operations like open()/fstat(), and this
>> will likely result in suboptimal nginx performance even if just
>> serving static files from such storage.
>>
>> Maxim Dounin
>>
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>
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