On 06/14/2013 07:15 AM, Stephan Viljoen wrote:
Hi There, I need to build a proxy server for an ISP handling about 4000 ip addresses over a 125Mbps of Internet bandwidth and were wondering what the specs for such a server would be? It's going to be a transparent squid server configured with Tproxy running as a bridge. I'm thinking of using around 16GB of RAM , two Quad core Xeon CPU's and about 8 SAS disks. Will this be enough or should I aim higher?
For an ISP one likes guaranteed uptime, so I recommend to consider 2 or more servers instead of one. Squid is limited by the number of requests/second. Find out what the current number is to properly size a set of proxies. There is a trade-off between using disks or not basically because disks are a relatively slow cache compared to memory cache and if your network pipe has sufficient capacity, also fetching an object again from the internet is can be faster than fetching from disk. With disks: - higher cache hit ratio / uses less bandwidth - slower if internet connection is fast - more expensive (disks + battery-backed I/O controller) - Squid uses more memory to index the disk cache (14 MB memory per GB disk cache) and hence less memory for in-memory cached objects Without disks: - lower cache hit ration / only use memory cache - faster if internet connection is fast enough - cheaper - Squid uses more of the available memory to cache in-memory objects. - unless a redundant hot-swap RAID array is used, less downtime. One can also redistribute budget: - use the budget of the disk system to max out memory. Rules of thumb: - put as much memory as possible. - carefully size the disk cache; not too large since Squid keeps the index in-memory - if using a disk cache, use fast disks and a very good caching I/O controller to get maximum disk performance Marcus
Some advice would be greatly appreciated. Thanks in advance, -steph
