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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Browser caching is generating hugo I/O to server

Our users My Documents are stored on a Emc NAS. I have noticed huge traffic coming from users and I see that most of it is coming to cache directories of Internet Explorer and other browsers. One ...
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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 ...
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1answer
175 views

Nginx issue with two web nodes

I'm running Wordpress website with Nginx and Memcached. I have simple DNS round robin balancing with A records pointing to both web servers. I've noticed the following entries in both web servers ...
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2answers
174 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 ...
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1answer
312 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 ...
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1answer
432 views

IIS 6 + ASP.NET Output Cache Not Working

As you can see from the title, our output cache is not working. We only recently noticed but it did at one time work (verifiable with a hidden timestamp at the bottom of the page; we cache for 3600 ...
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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 ...
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1answer
291 views

Nginx: read temporary cache file

I use ngx_http_proxy_module with proxy_ignore_client_abort to cache files. So when client close connection nginx will continue copying file from backend to current server. But when another user will ...
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1answer
169 views

Determine performance of disk cache in Linux 2.6.32+

I am hoping to find some good methods (by looking at /proc) or good tools that I can use to determine the effectiveness of the disk cache. I would like to be able to determine just how much of the RAM ...
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0answers
67 views

File-based reverse proxy cache with lru gc?

For a project I'm working on I need a file-based reverse proxy cache where I limit the size of the cache to some setting and have the ability to "gc" the cache based most likely on a lru algorithm. ...
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1answer
299 views

Credentials caching in OpenLDAP proxy

I am creating LDAP proxy server using OpenLDAP, server will be used for user authentication (using simple bind over SSL/TLS). Is there a way to make OpenLDAP proxy to cache simple bind credentials and ...
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0answers
412 views

ASP.NET, IS7 and IE8 caching?

We're suddenly having problems with some of our sites having old versions of .css and .js files show up in the browser. Generally, these problems go away, when the user clears cache in the browser. ...
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2answers
306 views

Requesting better explanation for expires headers

I have successfully implemented expires headers however, for several days I have been stumped by one thing. This article: ...
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1answer
319 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 ...
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1answer
94 views

news portal caching system

We have news portal. We have 5 identical dedicated boxes. 2xE5620, 16GB ram, 4x146gb 15k sas raid10. at this time bottleneck is mysql. One box is load balancer (nginx), two boxes (C,D) is nginx & ...
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3answers
260 views

Caching DNS. How does it choose what DNS server to query?

I have a local caching dns server (named). Say I want to resolve a blizzard.com domain. How does my local DNS manage to find the correct server to query for this domain? Does it have a list of other ...
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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 ...
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1answer
486 views

Django/MySQL/Memcached for 10K user visitors

I'm currently using CentOS (512 RAM, Dual-core CPU) for my website. Here are the specs: Django 1.3.1 Python 2.7.2 Apache 2 with mod_wsgi 3.3 MySQL 5 (about 5,000 records) Memcached (120 MB for ...
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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 ...
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2answers
436 views

reverse proxy and caching for a website

I come from Europe and in my country there are really expensive webservers, so i have my VPS server in the USA. Now i need on one hand a website with local IP and on other hand fast webserver. So i am ...
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4answers
310 views

HTTP resource caching / fetching

I'm trying to optimise a page, and I'm seeing some strange behaviour. Each time I click on a link to the page, all resources are fetched from the server, responding with 200s. However, when I refresh ...
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1answer
204 views

For IIS7 what is the default behavior when output caching has no rules added for .aspx files

If there are no rules for output caching under IIS7, would global.aspx or default.aspx pages be cached, by default, or not cached? I am trying to see if we need to explicitly turn off caching for two ...
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4answers
2k views

Downloads pause and time out frequently

I'm a new systems and network admin. My experience has been in the hardware and software of systems and servers, the network part is pretty new to me. I'm familiar with plugging numbers into network ...
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2answers
254 views

MySQL query caching - what happens if Server runs out of RAM?

so I have enabled query caching on my server but now from the 8 GB RAM there is almost non left! CPU is around 3% ! Now what happens when there is no more RAM left? Will this just increase CPU load? ...
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1answer
530 views

Caching an Umbraco website running on IIS 7.x with .NET 4.0 on an AWS EC2 instance

What are the available options for caching an Umbraco website on AWS EC2? So far, we've considered using Varnish but it's not recommended for a production environment. Is there a de-facto HTTP ...
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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 ...
9
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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 ...
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1answer
665 views

Server AppFabric Caching - What happens when the memory runs out

On my Windows Server 2008 R2 machine, I configured to use Server AppFabric Caching features. It has a nice API which I can implement as default caching provider on my ASP.NET MVC applications. One ...
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2answers
349 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), ...
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1answer
472 views

URL with trailing slash 404, appending index.php or ?someString works

Recently I've encountered an issue where some pages 404 when accessed via their cruftless paths. The same pages work when a query string, like ?1234 or index.php is appended to the path. Example: ...
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3answers
220 views

Cached content causing a huge number of 404 errors, too many connections

My site has been largely unresponsive for three days due to a large amount of traffic. A JavaScript element on the page regularly requested images from the server, and the number of connections ...
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2answers
838 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 ...
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1answer
86 views

Upgraded phpMyAdmin, can't see any changes in browser. Server caching?

How do I check if server caching is on, and is it okay to clear the cache (how do I do that?)? I have completely replaced all files in my phpMyAdmin directory so I'm not sure what else it could be. ...
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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 ...
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1answer
3k views

Memcached Cluster - better to have 3 smaller instances or 2 mediums ones?

Currently I have 2 small servers in an memcached cluster. We are approaching out limits with them and need to grow. What are the pros/cons or going adding another small instance compared with having 2 ...
6
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2answers
421 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 ...
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0answers
165 views

Is it possible to detect IIS kernel mode caching from the client?

My company has software that has a critical bug associated with kernel mode caching. We have distributed a fix, but we want to be aware of who has not applied the fix. I would like to know if it is ...
5
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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 ...
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1answer
256 views

Nginx: Cache only home page

How do I specify the location directive to cache my homepage without any filename or extension suffix. I need to cache only my home page at site.com and not anything under it(i.e ...
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1answer
394 views

nginx proxypass content 404s when adding caching location block

Below is my nginx conf - the location block for adding expires max to content is causing issues with content from the /internal proxied sites. nginx error log; 2011/11/22 15:51:23 [error] 22124#0: ...
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1answer
487 views

IIS 7: Expires header for specific files

I have this configuration for all static content on the site in the root directory: <configuration> <system.webServer> <staticContent> <clientCache ...
1
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1answer
345 views

Windows samba share: drop cache after DNS change

Suppose I have following entry in hosts.cfg file: 1.2.3.4 test # foo machine I start script that every second call ping test and cat \\test\share\machine-name.txt Script output: IP: 1.2.3.4; ...
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0answers
226 views

Oracle VirtualBox files being cached using shared folders

I'm hosting a static website (html/css/javascript) as a virtual host on a Fedora 15 Linux instance running Apache 2.2.21. for some strange reason, Apache seems to be caching the files even though I ...
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2answers
268 views

Buffer/Cache overflow Ubuntu 10.04 LTS Xen Rackspace

I'm running: Ubuntu 10.04 LTS Server AMD64 in a 512MB XEN paravirtualized environment. lighttpd v1.4.26 PHP v5.3.8 MySQL v5.1.41-3ubuntu12 The issue is: I first started on a '256MB account' which ...
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1answer
253 views

Nginx: Per user caching

For normal public pages & js I do a proxy_cache assets; proxy_cache_key backend$request_uri; proxy_cache_valid 200 302 100d; proxy_cache_valid 404 1m; ...
1
vote
3answers
843 views

Is using both Nginx and Varnish at the same time redudant?

Disclaimer: I'm not an expert on either Linux, Nginx, Varnish or anything related to servers but I've managed to get a Linode VPS up and running, serving two blogs with Wordpress on them to different ...
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1answer
51 views

Scalable server configuration for dynamic growing social site [closed]

My team is writing (social) website, witch should in theory grow up very fast. My task is to attempt to define the hardware requirements for such a page (for investors). Technology in which we create ...
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1answer
630 views

nginx proxy caching and ssi

I am using nginx for caching requests from the upstream apache server, however I want few blocks inside to be fetched from apache all the time. I am hoping ssi can do this, but the SSI tags are ...
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1answer
442 views

Caching 404s - NGINX or Varnished?

I'm looking for a solution to cache 404s in long term (a few days/weeks) on the webserver. My current setup is NGINX with memcached_pass proxy and PHP-FPM to deliver uncached pages (PHP also writes ...
0
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1answer
323 views

Caching and/or session issue with django application

We're having several issues with users getting logged out and/or not being able to sign in to our Django application. We have a single database, multiple front end servers, and a nginx load balancer ...