a cache stores temporary data nearby so that it can be retrieved much more quickly than fetching it from the real backing store (disk, network), or recalculating some result all over again

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45
votes
5answers
14k views

Drawbacks of using preload? Why isn't it included by default?

I would like to know what are the drawbacks of using preload? If there would be no downside, preload would be enabled by default, so I guess there are some. Okay you need a bit more RAM, but most ...
38
votes
4answers
17k views

How do I install and use flashcache/bcache to cache HDD to SSD?

I want to know if there is anyone who has tried installing and running their kernel built with flashcache or bcache for SSD caching? How did you manage to do it?
30
votes
3answers
27k views

Is it okay to delete ~/.cache?

When I use disk usage analyzer and scan my home folder .cache always shows up with a decent bit of things in it. Would it be okay for me to delete the contents of this folder or would it damage ...
21
votes
3answers
6k views

What is safe to exclude for a full system backup?

I'm looking for a list which paths/files are safe to exclude for a full system/home backup. Considering that I have a list of installed packages. /home/*/.thumbnails /home/*/.cache ...
18
votes
5answers
20k views

How do I use zRam?

I installed zRam as described on webupd8.org. I installed it from the terminal. Is that all I have to do or do I have to do some configuration or something? Does the zram-enabler do everything by ...
13
votes
2answers
4k views

Can I copy large files faster without using the file cache?

After adding the preload package, my applications seem to speed up but if I copy a large file, the file cache grows by more than double the size of the file. By transferring a single 3-4 GB ...
11
votes
2answers
12k views

How to clean var/cache/apt in a way that it leaves only the latest versions of each package

I want to know a way to clean the var/cache/apt folder in a way that it only leaves the latest version of a package if it has several versions or it leaves a package if it is the only one of that ...
11
votes
2answers
6k views

How do I reset the thumbnail cache?

I have a lot of images on my laptop as I work in graphics. On the same system, I also have a folder containing my family pictures. I would like to do two things: Empty the already cached images ...
10
votes
5answers
24k views

Best way to set up DNS caching?

In order to speed up DNS lookups, I want to install a DNS cache or proxy. I can see at least three programs I think will do the job: bind9, pdnsd, or dnsmasq. I would like to make sure that if I ...
10
votes
6answers
18k views

Errors in dmesg - Test WP failed, assume Write Enabled [duplicate]

I'm experiencing some problems with drive cache and I don't know what's causing these problems. This is my dmesg: [11690.011238] sd 6:0:0:0: [sdb] Asking for cache data failed [11690.011248] sd ...
9
votes
2answers
22k views

How do I clean or disable the memory cache?

After the system starts, in a few minutes my memory cache fills up and it starts using the swap. Here's a screenshot of /proc/meminfo. However, if I can disable this process / clean the cache once ...
9
votes
2answers
872 views

How to add packages to a squid-deb-proxy cache?

To save bandwidth and data on my Internet plan, I have installed squid-deb-proxy on a desktop, and the client on it and a few other machines I've got. However, based on the post that put me onto this ...
8
votes
3answers
845 views

Would there be any negative side-effects of sharing /var/cache/apt/ between two systems?

In the interest of conserving bandwidth, I'm considering mounting a VirtualBox host's /var/cache/apt as /var/cache/apt in the guest. Both host and guest are Ubuntu 10.10 32-bit. Would there be any ...
8
votes
3answers
5k views

How to clean caches in my homedir

My home directory is getting huge (100GB plus). When backupping it I notices that there are quite some caches there. Which important caches are there in my homedir and how should I clean them? One ...
8
votes
3answers
6k views

Computer freezing on almost full RAM, possibly disk cache problem

The problem I think is somewhat similar to this thread. It doesn't matter if I have swap enabled or disabled, whenever the real used RAM amount starts going close to maximum and there is almost no ...
7
votes
2answers
183 views

Does Ubuntu store data of external media/drives?

I keep confidential data (docs, spreadsheets, images, etc) on USB sticks or discs. I plug/insert them to access the data when I need, and put them back in a drawer when I'm done. Does Ubuntu store ...
7
votes
2answers
735 views

Get flash drive to cache disk reads to primary partition

Basically I'm looking for a way to mimic Windows' ReadyBoost. I asked this question on Unix.SE to get an idea of whether this was even possible and it seems like it is. Appparently there is a cachefs ...
6
votes
3answers
15k views

How do I increase cache size in Chrome?

is there any way to increase the cache size of google chrome in ubuntu 11.10 so that frequently visited pages load faster, im using a very-slow internet connection so i badly need this
6
votes
3answers
2k views

How do I tell what type of CPU cache is in my laptop?

Is there an application for Ubuntu that could tell me details about CPU, CPU cache memory, memory hierarchy, cache architecture implemented in my system, cpu cache size, cpu cache, access cycle and ...
6
votes
2answers
556 views

Tell the kernel to strongly cache a particular directory

This question is a rephrasing of Optimizing EXT4 performance. I have a directory that contains build files, most very small, but totaling 5.6G. I usually access the same subset of files (some ...
5
votes
3answers
2k views

Why does /var/cache/apt/archives keep deleting files

I normally download all .deb packages and just copy the packages from /var/cache/apt/archives directory to the rest of the computers, saving me to have to download all the updates and programs again. ...
5
votes
4answers
17k views

Why is the cache in my memory always full?

I have 6GB RAM, i5 2.4GHZ Processor running Ubuntu 11.10. I partitioned my HD so that I have 8GB swap. When streaming online or opening several tabs in Chromium I soon have 4GB Memory in the cache. ...
5
votes
2answers
1k views

Can an external flash or hard drive be used to boost performance, similar to Windows' ReadyBoost?

I have a number of spare external hard disk drives lying about the place and I was wondering if there is any practical way of using an external hard drive or USB flash memory drive to boost ...
5
votes
1answer
3k views

How to move the user cache directory [~/.cache] out of the /home directory to another partition

The .cache directory is full of volatile, non-essential files. I would like to move it to a more appropriate partition, i.e. faster and not backed up. I believe that ~/.pam_environment file is ...
5
votes
1answer
2k views

What is icon-theme.cache?

When I run the following command on my Lubuntu 12.10 [11:09 PM] ~ $ find /usr/share/icons/ -iname icon-theme.cache -type f I get the following (after adding the last modified date and size): ...
5
votes
1answer
614 views

Does dnscache really improve the surfing speed?

I have installed dnscache (dnscache-run) from Ubuntu repositories and I have increased the CACHESIZE and DATALIMIT to 256MB (268435456). Today I have tested it with one domain: google.es. I have ...
5
votes
3answers
2k views

How can I disable the prefetch cache?

I run a few Ubuntu servers that have a load of django sites running on them. The sites and the httpd start at boot and after that (apart from me SSHing in to update it or using bzr to update websites) ...
5
votes
2answers
463 views

Ubuntu tweak and Mozilla (firefox and thunderbird) cache

I usually use Ubuntu tweak to do cleanup jobs on my PC. This includes apt and program cached data and old kernels. This goes alright for most programs except Mozilla based application - Firefox and ...
5
votes
1answer
855 views

Safe to remove…?

I'm trying to customize a LiveCD, but I can't manage to fit it on a normal CD. So I investigated, and came across a few files of which I don't know if it's safe to remove them. Maybe you can help me ...
4
votes
1answer
4k views

Can I cache an mdadm raid with an ssd?

I have a 1TB array set up in raid 1 using mdadm on Ubuntu 8, to store mission-critical files. I'd like to speed up read/write, especially for large files by caching to an SSD. Is this possible? Does ...
4
votes
1answer
1k views

Retrieve Google Chrome Ubuntu favicon

Where the favicon .ico file is stored in Ubuntu 11.10? How can I extract the .ico file from the chrome cache?
4
votes
1answer
708 views

How to preload programs?

What I want to do is open some programs in the boot sequence so Ubuntu loads them into memory. I'm already using the preload package and it's not helping in that part. Thanks.
4
votes
1answer
203 views

When running locally, does Juju use the host machine's APT cache?

When juju fetches packages for a unit, does it make use of the host system's APT cache? I'm asking this because in my case, bandwidth is limited and I am doing some charm development. It is not ...
4
votes
1answer
106 views

Is it possible to recover unflushed data from the disk/page cache?

In Ubuntu, I move some file to a USB stick, using mv dir/file /media/7EXXX/swap/. When finishing this, I forget to "safely remove" before physically removing usb stick. Now, the file is not shown in ...
3
votes
3answers
272 views

Creating tar fills system cache

My situation is pretty simple: I backup-ed some of my documents and put them on a NAS and since I rather transfer one big file instead of million small ones, I created a tar tar cf ...
3
votes
3answers
10k views

Where does my browser store temporary data?

How can one look at content of temporary cache of his computer ? After something not actually downloaded (just pressing the button to open data not download) to any directory, this data temporarily ...
3
votes
1answer
1k views

What Does Cached Memory Mean when Viewing htop?

While viewing the reports of htop, I would like to know what the orange/brown 'cached memory' bars actually indicate. Really I'm looking for a more practical explanation of what I'm looking at, rather ...
3
votes
2answers
1k views

Can I use all my RAM for application data?

I have yet another question about "where is my Linux memory" Question goes: can I use cache for application data? On my laptop I have 1GB ram. Situation after some time of work: browser takes 400MB ...
3
votes
1answer
1k views

How can I clear my cached gpg password?

I've tried: the SIGHUP method --> no succes the cache timeout in gpg-agent.conf --> it seems that this file is not read, althougt I have the 'use-agent' line in gpg.conf What should I do ?
3
votes
3answers
1k views

Is there a desktop-wide privacy mode?

With Zeitgeist now tracking everything I really think we need a privacy mode like the one Firefox offers. There is a ridiculous amount of history and caches being stored in Ubuntu from thumbnails to ...
3
votes
1answer
497 views

What do these apt commands do?

What do these commands do? Acquire::http::No-Cache=True -o Acquire::BrokenProxy=true update Acquire::http::Max-Age "0"
3
votes
1answer
522 views

KVM host: Ubuntu 12.04 3.2 Kernel showing incorrect “cache size” in cpuinfo?

2x Xeon E5620 . 16 Cores altogether. /proc/cpuinfo shows cache is only @ 4096kb According to intel this should have 12MB of "smart cache". Doing searched for E5620 and CPUinfo shows the correct ...
3
votes
1answer
179 views

add packages to apt's partial archives

I'm experimenting with a possible answer for add packages to squid-deb-proxy cache, wherein I am trying to add files downloaded on a different network to the squid-deb-proxy cache. It occurred to me ...
3
votes
1answer
537 views

How to get apt to make files in /var/cache/apt/archives always world-readable?

I want the files in /var/cache/apt/archives to always have read permissions for everyone. That is, whenever apt downloads a new file into this directory, it should make it world-readable. This is not ...
3
votes
1answer
73 views

Disable memory cache - real reason

OK, before you mark my thread a duplicate I want to say, that I know this very good answer: How do I clean or disable the memory cache? But this is not case for me. I am making some performance tests ...
3
votes
0answers
43 views

What is the optimal configuration for a laptop with a 24GB SSD cache? [duplicate]

I have a Sony Vaio ultrabook that contains a 24GB ssd drive and a 750GB hard disk. What is the optimal configuration for installing ubuntu on this to get the most out of the hardware? Would I be ...
2
votes
3answers
530 views

Why does my system use so much cache?

Previously, on my desktop computer running Ubuntu 14.04, I had 4GB RAM, which I thought should be plenty. However, after being on for a while, my computer would seem to get slow. I have a system ...
2
votes
2answers
2k views

Is there a difference between SWAP and Cache memory?

I installed the indicator-multiload 0.2-0ubuntu1 from the software center. (It's very similar to the gnome panel indicator showing memory and CPU graphs) When I click on the Unity panel which shows ...
2
votes
3answers
985 views

What is the write-mode policy that is used in Ubuntu?

Is there anyway to see whether Ubuntu uses write through or write back policy? I know that write back is much better, but when I write a program in C to test the cache, it appears that Ubuntu uses ...
2
votes
1answer
3k views

How to tell if squid-deb-proxy is working?

I've got squid-deb-proxy, avahi-tools, and squid-deb-proxy-client installed on a gateway VM running 12.04 Server, and squid-deb-proxy-client installed on two client VMs running Lubuntu and Xubuntu ...