mod_cache caching cluster

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Hello, I was wondering if anyone has run across a means consolidating or
clustering their cache? Currently we have 20 nodes that only serve up
static content. Each node is configured with a 6G ramdisk
(mod_disk_cache). This works *ok* except for a couple issues. 1) We
experience intermittent performance issues (it seems to happen when
htcacheclean kicks off), and 2) the cache varies from machine to machine.

I was digging around with mod_memcache - I really like the idea but 1) it
doesn't look like it's actively developed, and 2) I can't seem to get the
caching to do what I want. I was also briefly looking at JCS - but that
maybe a little overkill?

I could have the content stored on a shared NFS mount but I wanted to stay
away from disk-based caching if I could.

If anyone has any suggestions or ideas I'd appreciate it greatly.

Matt

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Hello, I was wondering if anyone has run across a means consolidating or cl=
ustering their cache?=A0 Currently we have 20 nodes that only serve up stat=
ic content.=A0 Each node is configured with a 6G ramdisk (mod_disk_cache).=
=A0 This works *ok* except for a couple issues.=A0 1) We experience intermi=
ttent performance issues (it seems to happen when htcacheclean kicks off), =
and 2) the cache varies from machine to machine.


I was digging around with mod_memcache - I really like the idea but 1) =
it doesn't look like it's actively developed, and 2) I can't se=
em to get the caching to do what I want.=A0 I was also briefly looking at J=
CS - but that maybe a little overkill?


I could have the content stored on a shared NFS mount but I wanted to s=
tay away from disk-based caching if I could.

If anyone has any sugge=
stions or ideas I'd appreciate it greatly.

Matt


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Re: mod_cache caching cluster

Matthew Tice writes:

> I was digging around with mod_memcache - I really like the idea but 1) it
> doesn't look like it's actively developed, and 2) I can't seem to get the
> caching to do what I want.

Yes, mod_mem_cache development is pretty much stopped, and it's been
dropped from the next release of Apache. Also consider that mem_cache
would have an independent cache per process, which would be the reverse
of the consolidation you're looking for.


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Re: mod_cache caching cluster

On Mon, Dec 7, 2009 at 20:08, Matthew Tice wrote:
> Hello, I was wondering if anyone has run across a means consolidating or
> clustering their cache?  Currently we have 20 nodes that only serve =
up
> static content.  Each node is configured with a 6G ramdisk
> (mod_disk_cache).  This works *ok* except for a couple issues. =
1) We
> experience intermittent performance issues (it seems to happen when
> htcacheclean kicks off), and 2) the cache varies from machine to machine.
>
> I was digging around with mod_memcache - I really like the idea but 1) it
> doesn't look like it's actively developed, and 2) I can't seem to get the
> caching to do what I want.  I was also briefly looking at JCS - but =
that
> maybe a little overkill?
>
> I could have the content stored on a shared NFS mount but I wanted to sta=
y
> away from disk-based caching if I could.
>
> If anyone has any suggestions or ideas I'd appreciate it greatly.
>

Since it is only really static content, and provided that when a given
element changes, its URI changes, you should definitely look at
mod_expires:

ExpiresActive On


ExpiresDefault "access plus 1 month" # or more
Header append Cache-Control "private" # this tells that the proxy
won't cache, but the final client will


You don't even need disk-based caching. The OS' pagecache will largely
fill the "need for speed".

--=20

Francis Galiegue
ONE2TEAM
Ingénieur système
Mob : +33 (0) 683 877 875
Tel : +33 (0) 178 945 552
fge@one2team.com
40 avenue Raymond Poincaré
75116 Paris

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Re: Re: mod_cache caching cluster

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On Mon, Dec 7, 2009 at 12:23 PM, Dan Poirier wrote:

> Matthew Tice writes:
>
> > I was digging around with mod_memcache - I really like the idea but 1) it
> > doesn't look like it's actively developed, and 2) I can't seem to get the
> > caching to do what I want.
>
> Yes, mod_mem_cache development is pretty much stopped, and it's been
> dropped from the next release of Apache. Also consider that mem_cache
> would have an independent cache per process, which would be the reverse
> of the consolidation you're looking for.
>
>
Well, I was talking about mod_memcache (
http://code.google.com/p/modmemcache/) which seems to sort of be an
Apache-frontend for memcached servers. To get around using mod_mem_cache I
use mod_disk_cache on a ramdisk. It does great except for some reason I
can't get it to scale over 4G very well.

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Re: mod_cache caching cluster

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On Mon, Dec 7, 2009 at 4:04 PM, Francis GALIEGUE wrote:

> On Mon, Dec 7, 2009 at 20:08, Matthew Tice wrote:
> > Hello, I was wondering if anyone has run across a means consolidating or
> > clustering their cache? Currently we have 20 nodes that only serve up
> > static content. Each node is configured with a 6G ramdisk
> > (mod_disk_cache). This works *ok* except for a couple issues. 1) We
> > experience intermittent performance issues (it seems to happen when
> > htcacheclean kicks off), and 2) the cache varies from machine to machine.
> >
> > I was digging around with mod_memcache - I really like the idea but 1) it
> > doesn't look like it's actively developed, and 2) I can't seem to get the
> > caching to do what I want. I was also briefly looking at JCS - but that
> > maybe a little overkill?
> >
> > I could have the content stored on a shared NFS mount but I wanted to
> stay
> > away from disk-based caching if I could.
> >
> > If anyone has any suggestions or ideas I'd appreciate it greatly.
> >
>
> Since it is only really static content, and provided that when a given
> element changes, its URI changes, you should definitely look at
> mod_expires:
>
> ExpiresActive On
>
>
> ExpiresDefault "access plus 1 month" # or more
> Header append Cache-Control "private" # this tells that the proxy
> won't cache, but the final client will
>
>
> You don't even need disk-based caching. The OS' pagecache will largely
> fill the "need for speed".
>
> --
>

Thanks Francis, I'm a little confused about a couple things. 1) Is the
ExpiresDefault in mod_expires similar to CacheDefaultExpire in mod_cache?
2) This wouldn't address the need for a backend global cache? Also I
wanted to limit/reduce any kind of paging and it seems that with 9+G of
cache I would be swapping all over the place.

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