My first try with varnishd

[Anders Berg]

> [redirected to the mailing list]
>
> Jiang Hong <netex at 163.com> writes:
>> First congratulations to the 1.0 release of varnishd!
>
> Thank you!
>
>> The 'mmap' line told me varnishd uses mmap, so 1.6G cache file *SEEMED*
>> too
>> big for it (but isn't the limit 2GB?). Then I tried a 160MB cache file,
>> this
>> time varnishd started working!
>
> It successfully mapped the entire file, but for some reason there was
> too little address space left for malloc().  Try a slightly smaller
> file, or increase maxdsiz, or switch to a 64-bit machine.
>
>> So is it possible for varnishd to use multiple mmaps to use cache files
>> larger than 2GB? It is enough for most cases, but when the average file
>> size is larger than 2GB, it's much better to use a cache_dir like Squid.
>
> No, it's a matter of address space.  Varnish does not use a two-level
> cache like Squid, it uses a single cache which is backed by a file to
> allow the VM system to swap it out if it runs low on physical memory.
> On a 64-bit machine, you can create a cache file as big as your entire
> disk if you want.
>
>> Can '-s malloc' be used with '-s file'? Squid uses memory as level-1
>> cache
>> and disk storage as level-2 cache.
>
> No.  Squid's two-level cache is precisely one of things that's wrong
> with it.  It ends up fighting the VM system under heavy load.  Varnish
> on the other hand tries to avoid doing work which the VM system
> already does better (like deciding which objects should be in physical
> memory and which should be on disk).

Great text/answers for the FAQ, DES.

> Yes, I'm working on it.  For now, look through recent threads in the
> varnish-dev archive (http://projects.linpro.no/pipermail/varnish-dev/)

Great. I just wrote in another email that it was in /dev/null land for
now. Nothing is better than I was wrong.

Anders Berg