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List:       squid-users
Subject:    Re: [squid-users] Re: cache memory?
From:       Beto Moreno <pamrtj () gmail ! com>
Date:       2012-05-29 4:27:49
Message-ID: CAAJD-mCRLRiH68YBF-yr3ZoffWNkn6KSamt9kiG8iuDg9PyFPw () mail ! gmail ! com
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Very clear your information, appreciated, I'm being a little paranoid
hahaha, thanks!!!

On Mon, May 28, 2012 at 5:48 PM, Amos Jeffries <squid3@treenet.co.nz> wrote=
:
> On 29.05.2012 09:45, Beto Moreno wrote:
>>
>> Sorry, I didn't finish this post.
>>
>> 1 question, I will setup a cache server with squid 2.7.x, the server
>> will have 8GB of ram, the biggest service will be squid, I'm thinking
>> in 4GB for squid, 4GB other services.
>> I have seen that squid use part of the memory to save objects and some
>> times he return the cache from memory or disk, memory is faster we
>> know this, them this is one reason
>> that I want to give more memory to squid.
>>
>> Is what I understand, them if I'm right, what happen once U reboot my
>> server?
>>
>> What does squid to the object in memory?
>
>
> Squid tries to save what it can and terminate cleanly in the time allowed
> (shutdown_timeout).
>
>> Do I lost them?
>
>
> There is a very important concept to keep in mind here which is often
> overlooked:
>
> =A0*** Cache is temporary storage ***. Emphasis on "temporary". It is
> Constantly renewed from network sources.
>
> As a result no content is ever "lost". Even should you completely erase t=
he
> cache contents and restart from a clean-slate, everything is still availa=
ble
> from the relevant origins/master server somewhere out on the network.
>
>
>
>
>> Or haven't understand how squid use the memory?
>
>
> You seem to understand the usage okay. But you are fixated a bit on hoard=
ing
> data.
>
> The only side-effect of rebooting the server is a short "full" outage of
> service, and a short period of slightly slower service as the caches are
> re-filled.
>
> This may sound bad at first glance, but it is a tradeoff between network =
and
> disk re-builds. Even if everything was saved to disk across the reboot th=
ere
> is still a slow period from disk I/O latency and CPU to re-populate the
> memory indexes. Versus network lag of fetching a clean copy.
>
> Squid has automatic client new-connection damping/buffering to cope with
> both these periods and DoS situations without actually loosing clients
> requests.
>
> Amos
>
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