In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster.

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25
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5answers
28k views

Setting expires headers for static content served from nginx

I'm using nginx to server my static content, is there a way that I can set the expires headers for every file that meets a specific rule? For example can I set the expires header for all files that ...
21
votes
18answers
21k views

Caching/preloading files on Linux into RAM

I have a rather old server that has 4GB of RAM and it is pretty much serving the same files all day, but it is doing so from the hard drive while 3GBs of RAM are "free". Anyone who has ever tried ...
10
votes
3answers
4k views

Tuning Linux disk caching behaviour for maximum throughput

I'm running into a maximum throughput issue here and need some advice on which way to tune my knobs. We're running a 10Gbit fileserver for backup distribution. It's a two disk S-ATA2 setup on an LSI ...
10
votes
5answers
11k views

How to load-balance SQL Server 2008 for high-usage ASP.NET applications?

Imagine that you have a successful web application that uses ASP.NET and IIS 7. It generates many calls to a SQL Server 2008 database, and is expected to be available to the public with 99.9% uptime ...
9
votes
1answer
1k views

Stop IIS 7.5 From Sending Out Cache-Control Max-Age on Error Codes

I have some static content with cache control Max-Age headers attached to it so clients will cache the static content. However, IIS 7.5 still sends this header out when there are error responses ...
9
votes
3answers
388 views

Irregular internet disruption: certain images and JS not loading

first time on ServerFault, and I've got a nice little conundrum. Since a few months now, we've been having issues with our internet connectivity. Environment: Servers: 2 Terminal Servers as an ...
8
votes
2answers
7k views

Varnish Cache - default TTL?

I have discovered that I can set the TTL in Varnish as follows in my VCL file: sub vcl_fetch { # 1 minute set obj.ttl = 1m; } But what is the default setting (assuming the backend server is ...
8
votes
5answers
18k views

Is there a way to turn off client browser caching for specific websites?

This is a browser agnostic question but we're testing with IE9. One of the web apps our users visit is being randomly cached and changes aren't showing up when they should. No other site has this ...
7
votes
3answers
24k views

How do I disable tomcat caching? I'm having weird static file problems

How do I prevent tomcat from caching? I have css and basic html files that I load and use via ajax, and unless I restart tomcat, the changes do not seem to reflect. Different machines, different ...
7
votes
3answers
2k views

Caching youtube on LAN [duplicate]

Possible Duplicate: How can I cache YouTube videos with Squid Cache? I am an Administrator for a net cafe. We have limited monthly traffic allowance and in past our investigations showed ...
6
votes
2answers
119 views

Caching db results - need a nudge on how to start

I have a project coming up where one of the requirements will be to cache what's essentially read-only data in order to lessen the strain on the db. I'm just a bit confused on how caching works with ...
6
votes
2answers
423 views

Windows File Cache drops suddently

I have a 64-bit Windows 2003 server with 48 CPU cores and 128GB of RAM running a single application (SQL 2008 Analysis Services). SSAS is currently using about 50GB of memory. SSAS relies to a ...
6
votes
4answers
161 views

Reading material for server architectures

I am currently part of a team working on a new large-scale project consisting of a web platform with content consumed through an API by various mobile devices. We really anticipate a lot of traffic ...
5
votes
3answers
4k views

Speeding up Apache and PHP

What are some good modules or systems that for caching that I can use for decreasing my load on Apache on an EC2 server running PHP, and why would you choose them?
5
votes
1answer
130 views

what harm can writeback caching have on a degraded disk array?

At work I administer several machines using (real) hardware raid controllers (with battery backed write caches), and these have the nasty habit of falling back to writethrough behaviour when an array ...
5
votes
1answer
704 views

How do I monitor memcached evictions?

How do I monitor memcached to know if / how many evictions are occurring, and how much memory is used/free.
5
votes
5answers
269 views

Identical traffic

I am running an application server and logging all requests for analysis purposes later. One interesting trend I noticed last night was, I had a visitor from Texas on FIOS share identical traffic ...
5
votes
2answers
781 views

Apache's htcacheclean doesn't scale: How to tame a huge Apache disk_cache?

We have an Apache setup with a huge disk_cache (>500.000 entries, >50 GB disk space used). The cache grows by 16 GB every day. My problem is that the cache seems to be growing nearly as fast as it's ...
5
votes
2answers
2k views

Main differences between SSI (Server Side Include) and ESI (Edge Side include)

I need to include dynamic content into static pages at web server level. The 2 options I have found so far are Server Side Include (SSI) and Edge Side Include (ESI). While the origins of SSI seem ...
5
votes
2answers
144 views

Slower/cached Linux file system required

I know it sounds odd but I need a slower or cached filesystem. I have a lot of firewalls that are syslog'ing their data to a pair of Linux VMs which write these files to their 'local' (actually FC ...
5
votes
3answers
3k views

Akamai vs smaller CDN for small/medium-size ecommerce traffic? (caching, latency, NetStorage)

The small/medium sized online retail company I work for uses Akamai as our CDN for static images, but I'm wondering whether it might be hurting rather than helping and, if it's suboptimal, what we ...
5
votes
3answers
4k views

Nginx & PHP caching: fastcgi_cache, proxy_cache, APC or memcached or combo?

We have webservers running nginx 7.65 along with fastcgi PHP5 and are looking into caching possibilities to speed up content delivery and lower system loads. The servers run different (custom) ...
5
votes
2answers
175 views

Cache updates when migrating DNS from one provider to another

This may be a Windows DNS specific question or a general DNS best practice question - I'm not sure! We migrated our 3rd party DNS provision from provider A to provider B. I noticed that our internal ...
4
votes
7answers
2k views

Scaling large file downloads?

We currently deliver large (1GB+) files via a single Apache server, but our Apache server is extremely disk-IO-bound and we need to scale. My first idea was to simply duplicate this Apache server, ...
4
votes
2answers
854 views

Can I use an SSD as Cache to a NAS?

There is a NAS with Raid 10 that holds resources. At a time, around 24 machines try to access the same resource (3d rendering in a render farm). Although the network is 1Gbps and NAS is fast, the ...
4
votes
1answer
209 views

Data syncing behavior for filesystems in Windows

In Linux mounting supports commit option, which is described in mount(8) man page as: commit=nrsec Sync all data and metadata every nrsec seconds. The default value is 5 seconds. Zero ...
4
votes
3answers
4k views

Akamai NetStorage vs. Akamai edge service

What's the difference between using Akamai NetStorage vs. Akamai's Edge Service? Below are the concepts that I believe differentiate them but I'd like more details from more experienced people. ...
4
votes
2answers
2k views

Caching proxy for yum and debian repositories

Does a caching proxy for yum exist, similar to approx for Debian repositories? Is there a way to have reprepro behave the same as approx? I have heard that approx was not as stable; besides, I would ...
4
votes
1answer
322 views

Combining Heroku with custom external services (e. g. Varnish or Postgres on EC2)

I'm planning to set up a Django site on Heroku. It will run on Heroku's Cedar stack, which allows Python apps, but doesn't include or support HTTP upstream caching with Varnish like the other stacks ...
4
votes
2answers
2k views

Optimizing MySQL for small VPS

I'm trying to optimize my MySQL config for a verrry small VPS. The VPS is also running NGINX/PHP-FPM and Magento; all with a limit of 250MB of RAM. This is an output of MySQL Tuner... -------- ...
3
votes
6answers
1k views

Fail-over caching reverse proxy

Is there a way to configure varnish or any other caching reverse proxy, to serve pages from its cache when the back-end fails? At the moment, if the back-end goes down a 503 Service Unavailable error ...
3
votes
2answers
287 views

What's the best wordpress cache plugin for a moderately trafficked server?

I'm supporting a moderately trafficked Wordpress server, with 2GB ram and a dual-core amd opteron CPU, running Gentoo. It looks like it's just a default install, so I'll be tuning mysql, but I'm also ...
3
votes
1answer
319 views

Making NFS behave like a block device

We're currently working on a virtualization setup, and because of features like being able to grow volumes on our filers rather than having to go through the process resizing block devices etc. we'd ...
3
votes
1answer
1k views

Nginx reverse proxy: Not setting expires header

I have my static assets configured as location @upstream { proxy_pass http://localhost:82; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; ...
3
votes
4answers
3k views

APC (PHP Cache) Uptime 0 minutes, not caching

My goal is to implement APC for opcode cache for a drupal 6 production site. I have so far tested APC with several php files with and without including other php files with include_once. Also tried ...
3
votes
1answer
124 views

Caching + webserver on the same machine?

I'm preparing the move of a live website from a shared server to a seperate server running just that one site. Right now we're getting lots of traffic and Apache is having a hard time keeping up. One ...
3
votes
1answer
2k views

Limiting bandwidth of workstations in MS Forefront TMG

We have configured Microsoft forefront TMG 2010 Enterprise as the cache server which provides internet access for all computers in our department. Is there any way to limit download speed per ...
3
votes
4answers
3k views

Caching DNS server (bind9.2) CPU usage is so so so high

I have a caching-only dns server which get ~3k queries per second. Here is specs: Xeon dual-core 2,8GHz 4GB of RAM Centos 5x (kernel 2.6.18-164.15.1.el5PAE) bind 9.4.2 rndc status: recursive ...
3
votes
1answer
207 views

What is the standard way to deploy memcached?

I have two IIS servers and two MySQL servers. On all servers I have some available memory (More than a GB). What is the standard way to deploy memcached? Should I add a new server especially for ...
3
votes
2answers
3k views

How to Cache dynamic content using Nginx when sessions are involved?

This link explains how to create static files from dynamic content using Nginx. My question is this: can I achieve the same if login sessions are involved. ie. when I want to serve content to only ...
3
votes
1answer
94 views

iozone: 5 concurrent threads random read of 300K blocks does more ops/s than using only one thread, what could be the underlying reason?

The partition is in RAID1 using software RAID. Command line used: iozone -s 190g -r 300k -O -b test_file OPS Mode. Output is in operations per second. ...
3
votes
1answer
531 views

flashcache with mdadm and LVM

I am having trouble setting up flashcache on a system with LVM and mdadm, I suspect I am either just missing an obvious step or getting some mapping wrong and hoped someone could point me in the right ...
3
votes
1answer
106 views

Loading of Home taking too long

We have a shared storage from NetApp mounted onto about 80 systems (all running Ubuntu 10.04 64 bit). These days there is some problem with the loading of user homes onto the lab machines ...
3
votes
2answers
360 views

How to map a folder to memory?

Is there a way to map a particular folder to memory? Say I have C:\somePath and I want that folder to be in memory at all times and maybe changes are dumped to HDD asynchronously without my notice. So ...
2
votes
2answers
3k views

Non-volatile cache RAID controllers: what kind of protection is there against NVCACHE failure?

The battery back-up (BBU) model: admin enables write-back cache with BBU writes are cached to the RAID controller's RAM (major performance benefit) the battery saves uncommitted and cached data in ...
2
votes
2answers
290 views

Varnish micro-caching

Micro-caching and Nginx can really speed up the app. Would it be possible to use micro-caching (or something similar) with Varnish?
2
votes
4answers
1k views

What caching strategies can I implement between my web load balancer and my web farm?

I've got a web farm of IIS7 machines. works great. We're about to release an API to the wild. It's pretty simple but we know it's going to get hit pretty hard from day one (we have at least one signed ...
2
votes
2answers
760 views

Varnish going sick

I'm having trouble with Varnish, it works for a couple of views and then just goes sick... The weird thing is that it does work for about 20 or 30 requests. If I call apache directly it works fine. ...
2
votes
2answers
358 views

Do Windows Servers (2008) cache .net assemblies somehow?

A co-worker of mine is having the following issue (so some relevant details may require further vetting): The server is Windows 2008 Server. There is a Windows Service that is running (exe (.net), ...
2
votes
1answer
1k views

Purge varnish cache for a single url using varnishadm

Varnish is being used in a Wordpress website. I would like to purge Varnish for a single URL instead of a whole domain. With this command I can restart Varnish for the whole domain: varnishadm -T ...