[squid-users] How much disk space is reclaimed by the cache replacement algorithms?

Hi,

Using LRU replacement policy, I see many of the cached webpages for my
site getting evicted. Could someone here tell me:

1. How often is the replacement done?

2. Lets say the cache low water mark is set to 95, I understand that
once the disk usage exceeds 95%, cache replacement kicks in. Once the
process is completed, what would the disk usage drop to?

3. I notice some pages in the cache_dir which are over a month old.
Doing a "curl" to the squid cache with the URL of the cached page causes
a TCP_REFRESH_MISS/FIRST_UP_PARENT entry to be logged in the access log.
Which means, the page has become stale (by the refresh pattern rules) on
the web cache and a new page is fetched from the parent site. From this,
I infer that the page hasn't been referenced in the last one month and
yet hasn't been marked for cache replacement while other newer cached
pages have been flushed out. Why's that?

Appreciate your response.
Thanks!

CONFIDENTIALITY NOTICE
=======================
This email message and any attachments are for the exclusive use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message along with any attachments, from your computer system. If you are the intended recipient, please be advised that the content of this message is subject to access, review and disclosure by the sender's Email System Administrator.
Received on Wed Dec 23 2009 - 01:45:44 MST