Re: [squid-users] Caching Video Content

> Hi,
>
> I am considering implementing Squid as my web cache for Video streams
> (YouTube etc).
> I am going to configure Squid over SAN centralized storage.
> I am aware of the additional plug-in required to "normalize" YouTube
> URL's.
> I have few questions:
> 1) Are there any example installations of Squid as Video oriented cache
> server?

I'm not aware of anything published.

> 2) If I implement Squid peering (either digest or ICAP), how does

I think you mean: CARP.
ICAP is a filtering or adaptation method.

> Squid solves "popular object" problem, when one cache within the
> cluster serves the most popular movie. As far as I understand, in this
> case all requests for that movie would be served from one particular
> server; this will cause overloading of that server.

The versions of Squid-2 which have the storeurl features for normalizing
you-tube requests also contain collapsed_forwarding which damps this type
of overload down a lot. Squid efficiency rises enormously under this type
of hot-object scenario up to close around 100% on the single object. Note
this occurs at BOTH levels of the squid mesh, receiving and source Squids
doing effective multicast for HTTP.

This is one reason CDN people love Squid so much.

> 3) Are there any limitations / recommendations for maximal storage
> size that has many separate physical disks?

No more than one cache_dir per disk. Squid can easily handle up to 63
cache_dir entries and thus disks. Beyond that certain types of RAID do
actually start to be useful.

> 4) Are there any limitations regarding maximal cached object size?
>

Squid-2 has 4KB buffers to store objects, so the larger ones have some
issues doing read seeks. I forget what the limits were.

Amos
Received on Thu May 21 2009 - 03:26:24 MDT