TCP_HIT and TCP_MEM_HIT

[J. Peng]

what's the difference between TCP_HIT and TCP_MEM_HIT ?

I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?

thanks!

[Marcello Romani]

J. Peng ha scritto:
> what's the difference between TCP_HIT and TCP_MEM_HIT ?
>
> I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?
>
> thanks!
>

I found this page by googling for squid TCP_HIT

http://www.linofee.org/~jel/proxy/Squid/accesslog.shtml

HTH

--
Marcello Romani
Responsabile IT
Ottotecnica s.r.l.
http://www.ottotecnica.com

[Marcello Romani]

J. Peng ha scritto:
> what's the difference between TCP_HIT and TCP_MEM_HIT ?
>
> I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?
>
> thanks!
>

Maybe this is better...

http://www.comfsm.fm/computing/squid/FAQ-6.html

--
Marcello Romani
Responsabile IT
Ottotecnica s.r.l.
http://www.ottotecnica.com

[Leonardo Rodrigues Magalhães]

J. Peng escreveu:
> what's the difference between TCP_HIT and TCP_MEM_HIT ?
>
> I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?
>
>  
    TCP_HIT happens when squid took the requested information from the
cache directories, ie, from the disk.

    TCP_MEM_HIT happens when squid took the requested information from
memory, ie, RAM memory.

    Of course you'll see less TCP_MEM_HIT than TCP_HIT because the
amount of memory and disk are VERY big. I dont know your situation, but
usually we have several GBs of cache in disk and only some few hundreds
of RAM memory allocated to squid. That's because you'll almost always
see a LOT of TCP_HIT and only some few TCP_MEM_HIT.

--


        Atenciosamente / Sincerily,
        Leonardo Rodrigues
        Solutti Tecnologia
        http://www.solutti.com.br

        Minha armadilha de SPAM, NÃO mandem email
        gertrudes@...
        My SPAMTRAP, do not email it

[pokeman]

TCP HIT is contain object in harddrive and TCP_MEM_HIT contain object in memory

J. Peng wrote:

what's the difference between TCP_HIT and TCP_MEM_HIT ?

I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?

thanks!

[Chris Robertson-2]

Marcello Romani wrote:

> J. Peng ha scritto:
>> what's the difference between TCP_HIT and TCP_MEM_HIT ?
>>
>> I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it right?
>>
>> thanks!
>>
>
> Maybe this is better...
>
> http://www.comfsm.fm/computing/squid/FAQ-6.html
>

Or you could go to the source...

http://wiki.squid-cache.org/SquidFaq/SquidLogs

Chris

[J. Peng]

On Fri, Feb 15, 2008 at 8:18 PM, pokeman <asifbakali@...> wrote:
>
>  TCP HIT is contain object in harddrive and TCP_MEM_HIT contain object in
>  memory
>

hello,

My squid has 2.0G mem totally, I assign 1.8G to squid's cache
buffer,the max object size I set is 128kb, and most of our files' size
is less than 32kb.
Why I still saw lots of TCP_HIT rather than TCP_MEM_HIT? thanks!

[Adrian Chadd]

On Sat, Feb 16, 2008, J. Peng wrote:

> My squid has 2.0G mem totally, I assign 1.8G to squid's cache
> buffer,the max object size I set is 128kb, and most of our files' size
> is less than 32kb.
> Why I still saw lots of TCP_HIT rather than TCP_MEM_HIT? thanks!

so you've set cache_mem at 1.8gig?

TCP_MEM_HIT is "objects that squid has in memory".
TCP_HIT is "objects that squid had to read from disk, and this may or may
not involve the operating system disk buffer."



adrian

--
- Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support -
- $25/pm entry-level VPSes w/ capped bandwidth charges available in WA -

[J. Peng]

On Sat, Feb 16, 2008 at 12:36 PM, Adrian Chadd <adrian@...> wrote:
> On Sat, Feb 16, 2008, J. Peng wrote:
>
>  > My squid has 2.0G mem totally, I assign 1.8G to squid's cache
>  > buffer,the max object size I set is 128kb, and most of our files' size
>  > is less than 32kb.
>  > Why I still saw lots of TCP_HIT rather than TCP_MEM_HIT? thanks!
>
>  so you've set cache_mem at 1.8gig?
>

yes, cache_mem is 1.8GB.
so I thought I should see much more TCP_MEM_HIT than TCP_HIT, but it is not.

[Adrian Chadd]

On Sat, Feb 16, 2008, J. Peng wrote:

> yes, cache_mem is 1.8GB.
> so I thought I should see much more TCP_MEM_HIT than TCP_HIT, but it is not.

It depends on your object workload. If you have quite a few large objects
going through your cache then it may throw out smaller objects which are
hit later.

Its hard to know without running some logs through an analyser. And I don't
know of anything publicly released that can help you optimise that sort of
stuff..


Adrian

--
- Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support -
- $25/pm entry-level VPSes w/ capped bandwidth charges available in WA -

[Chris Woodfield]

Before you go and say "wow, I want more MEM_HIT, increase mem_cache!",  
remember that if you have a decent amount of spare memory, the kernel  
will use that as page cache, so it's a good change that frequenty-
requested items will, in fact, be served from RAM (via the page cache)  
even if it's not squid's RAM. There's also a design bottleneck in  
squid that limits cpu efficiency of large mem_cache objects (larger  
than a MB or so), so resist the urge to give squid all your available  
memory. Let mem_cache handle your small objects and the kernel handle  
the larger ones.

-C

On Feb 15, 2008, at 4:18 AM, pokeman wrote:

>
> TCP HIT is contain object in harddrive and TCP_MEM_HIT contain  
> object in
> memory
>
> J. Peng wrote:
>>
>> what's the difference between TCP_HIT and TCP_MEM_HIT ?
>>
>> I found access.log has full of TCP_HIT but few TCP_MEM_HIT, is it  
>> right?
>>
>> thanks!
>>
>>
>
> --
> View this message in context: http://www.nabble.com/TCP_HIT-and-TCP_MEM_HIT-tp15498612p15499973.html
> Sent from the Squid - Users mailing list archive at Nabble.com.
>