[squid-users] Cannot purge items that are not upstream anymore

[Amos Jeffries]

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On 13/11/2014 12:17 a.m., Hussam Al-Tayeb wrote:
> Hello. I have a problem with 'squidclient -m PURGE' and also the
> purge command. They won't purge urls from disk that are not
> available online anymore or redirect to other links.
> 

PURGE was designed for use in HTTP/1.0. It does not handle HTTP/1.1
negotiated content / variants at all well.

> 
> For example, 
> http://static.firedrive.com/dynamic/previews/75/27577be2d6d86af20265734b64e8d563.jpg
>
> 
which corresponds to /home/squid/00/BB/0000BBC0
> 
> Even "purge -e "static.firedrive.com" -c /etc/squid/squid.conf -P
> 0x01" reads it but will not really remove it from disk. Are such
> files stuck on disk forever?

No. Cache is a temporary storage location. Think of it as a buffer in
the network.

They will exist only until a) the storage space is needed for
something else, or b) the timestamp in their Expires: header, or c) an
origin server informs Squid they are no longer existing.

PURGE method was a way to fake (c).


> What would the correct way to clear them?

By obeying HTTP protocol. HTTP has built-in mechanisms for doing that
automatically.

Or you can just delete the disk file. Squid will auto-detect the
removal at some point when it needs to use or delete the object. Until
then it will just under-count the amount of used disk.

Amos

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