June 2001
Intermediate to advanced
320 pages
9h 18m
English
Content preview from Web CachingBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Memory
Caching products vary greatly in how they use RAM. Some caches, notably Squid, keep a number of indexes in memory. The indexes have an entry for every cache object, such that index memory requirements are proportional to cache size. Most caching products also use memory to store popular or recently requested objects. Storing popular objects entirely in memory results in a performance improvement. Caches also use memory to pass data to and from the network. The amount of memory used for network buffers is proportional to the load on the system.
Memory starvation can be a serious problem. It is certainly serious for Unix-based solutions, such as Squid. When the application needs more memory than is physically available, some of the process memory is written to disk. Performance degrades very quickly when swapping occurs.
If you’re thinking about an appliance-based solution, you probably don’t have to worry about memory configurations. The product should come with an appropriate amount of memory, based on the particular software and other hardware components. If additional memory is available for your product, it may boost the cache’s performance by holding extra objects in memory.
If you’re using a software-based product, you’ll need to find out the amount of memory the vendor recommends. Current versions of Squid require a lot of memory compared to other products (including appliances). For Squid, I typically recommend 1MB of RAM for every 32MB of disk capacity. A significant ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.