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6
votes
1answer
571 views

How to use an SSD for caching, so my hard disks can spin down?

I've got a file server with a bunch of disks running together in a BTRFS pool and want to add an SSD for caching. I'm not mainly after speeding up things, but want to catch the regular small accesses ...
4
votes
1answer
67 views

Avoid -dbg_version packages on apt-cacher-ng server

Intro: We have created a apt-cacher-ng server to provide cached packages to our users that have Ubuntu 14.04 installed. Combined with the cached packages, we are doing a weekly "mirror" of some Ubuntu ...
4
votes
1answer
2k views

What options are there for tuning Linux file system caching?

What various types of caching are possible in the ext3 file system and how can their values be changed using system calls or other methods? I don't want to use commands or tools.
3
votes
1answer
103 views

Artificially prime buffer cache?

Is it beneficial to artificially prime the buffer cache when dealing with larger files? Here's a scenario: A large file needs to be processed, line by line. Conceptually, it is easy to parallelize ...
2
votes
1answer
82 views

Monitoring file reads for cache warming

After adding more memory to my Linux machine I was tempted to use the cache more agressively. The thing is: I boot up my machine, go to bathroom, come back and log in. It takes like half a minute to ...
1
vote
1answer
141 views

Request header for Cache-Control not working

I have set Cache-Control in apache for 1 week for my JS Files but when i check in the browser Cache-Control shows no-cache. Where i am missing the configuration ? Below is my configuration in apache ...
0
votes
1answer
302 views

flashcache tuning

I installed flashcache version 3.1.1 and created a write-back cache. The performance is good as long as the percentage of dirty blocks is not too high. My application does heavy IO at the beginning ...
0
votes
1answer
61 views

Is there a way to prevent SWAP from collecting cached data?

Here is the following info: Do I need more swap? No, disk caching only borrows the ram that applications don't currently want. It will not use swap. If applications want more memory, they ...
0
votes
1answer
50 views

How to print a Bind10 cache dump?

How can you print the current state of the bind10 cache? I searched the bind10 manual and tried to figure it out using bindctl.
6
votes
0answers
487 views

Cleanup of temporary file ~/.cache/duplicity/temp failed

Often when I run Duplicity I see an error message like this at the end of the run: Cleanup of temporary file ...
3
votes
0answers
30 views

Limit the inode cache used by a command

I want to run a task with limits on the kernel objects that they will indirectly trigger. Note that this is not about the memory, threads, etc. used by the application, but about memory used by the ...
3
votes
0answers
33 views

How to generate graphs from lmbench results?

I need to use the lmbench benchmarking tool to get the system performance statistics. I am able to execute and run the results. In the results folder this is a MakeFile with this information # ...
3
votes
0answers
62 views

Discover what is cached by dm-cache

I am using dm-cache successfully for quite a while now. Now I would like to know which files are being currently in the cache. I understand that dm-cache works with blocks, not files, but since there ...
3
votes
0answers
91 views

Figuring out physical cache layout in FreeBSD

I'm trying to figure out they physical cache layout of my CPU in FreeBSD 10. I see the following from sysctl kern.sched.topology_spec kern.sched.topology_spec: <groups> <group level="1" ...
3
votes
0answers
898 views

Tune write disk cache flushing algorithm

I would like to use the free memory for write cache. Linux does that automatically, but it has some weird flushing algorithm that I would like tuned for my use. I have recently used ddrescue to copy ...
2
votes
0answers
61 views

Restore /var/cache files

I've accidentally deleted all contents of /var/cache files. I managed to reinstall most by doing dpkg -S /var/cache and apt-get --reinstall install PACKAGE_NAME (see here) on every package that I've ...
2
votes
0answers
118 views

Reduce cache size of flash storage devices

For various benefits Linux uses a memory cache for writes to removable stogare devices like memory sticks. This cache seems to be quite large on my system, which leads to some annoying behavior. For ...
2
votes
0answers
44 views

In meminfo, sometimes Mapped more than Cached

In /proc/meminfo, AFAIK Cached >= Mapped But after /proc/sys/vm/drop_caches, it goes to Cached < Mapped Cached: 66132 kB Mapped: 67792 kB /proc/meminfo contents ...
2
votes
0answers
539 views

Route all HTTP traffic through polipo

I've set up polipo on my machine to listen to the default port 8123. To test it, I set the in-memory cache to a ridiculously high 2 GB and downloaded a 50 MB file using wget utilizing the proxy. ...
2
votes
0answers
61 views

Too large cache causes disks to grind, I/O to drop

This is a followup question to my earlier problem. In short I was experiencing massive I/O drops together with not-so-violent disk grinding, and with help I found out that the big caches were the ...
2
votes
0answers
817 views

Linux kernel slab usage growing on embedded system

I'm in the process of QA/debugging a project on a custom embedded linux system. The problem we're VERY tight on memory, and even a couple megs can cause issues with our software. What I'm seeing ...
1
vote
0answers
29 views

how to clear NFS client side cache and server side cache?

I would like to know what is the cache size NFS is using at client side and server side. How to clear it.? Is there a difference between system cache and network cache ?
1
vote
0answers
32 views

Out of Memory with unused memory and swap

I have a strange error on my Raspberry Pi2. System is archlinuxarm. Short after boot (about 30 secs), the system states that it is out of memory, resulting in closing many applications, most time ...
1
vote
0answers
44 views

How shareable is /var/cache?

I know that some subdirectories of /var/cache are pretty much shareable, for example /var/cache/pacman (in case of ArchLinux), and possibly others (/var/cache/man?), but at least /var/cache/ldconfig ...
1
vote
0answers
35 views

Very strange issue, something is blocking specific links on local domain

I have a very strange issue and I ran out of ideas. The major problem is that the symptoms are not consistent. I have a short link website hosted on 2 virtual machines, one with nginx+php-fpm and one ...
1
vote
0answers
296 views

Ubuntu: Restore not printed document from browser cache

I was at work today faced with a situation where I have to prove that I did not make a mistake. Without going into detail, yesterday I generated an important document which was to be printed. For ...
1
vote
0answers
31 views

Can not analyze output from Squid and varnish

I'm using one Squid server between tow cache server. I get from headers following information: X-Cache MISS, HIT from cache-zz X-Cache-Age 515 X-Cache-Control public, max-age=3600 X-Cache-Lookup HIT ...
1
vote
0answers
1k views

How to set up ZFS with ZIL and L2ARC SSD?

I have been considering bcache and flashcache. However my friend suggested me something called ZFS. In fact it says that formating disk with ZFS can actually do the exact same thing without kernel ...
0
votes
0answers
11 views

Change Linux Bcache device type

I have accidentally configured my SSD as a backing device instead of a caching device. Simply trying either one of the following: sudo make-bcache -C /dev/sdb1 sudo make-bcache -C /dev/sdb Gives ...
0
votes
0answers
29 views

Linux - is it possible to limit VFS cache usage on a per-process basis

I'm trying to investigate performance degradations while running background copy operations (using dd to write or read large disk-images). Is it possible to limit VFS cache usage for a single ...
0
votes
0answers
76 views

Using Varnish + Nginx Forcing SSL

i'm using Varnish and i would like to force communication only with SSL. My server is Nginx. What's the best way to do so? Or the easiest? I read about Pound proxy and installed it but guides were too ...
0
votes
0answers
77 views

Booting from an lvm-cached volume

I created a cache pool following this article. The process seems to be successful. After doing an upgrade-grub and rebooting, Grub complains that it can not find the root volume (showing a UUID). - ...
0
votes
0answers
106 views

Can't configure NGINX to cache images

I have been trying to cache images that are stored in nginx server, I am quite new here and to nginx I have installed it and configure it with php5-fpm, I have been reading many tutorial regarding ...
0
votes
0answers
107 views

Real copy to Android device

When i copy files to the Android phone, they are copied to some cache, but they aren't written. I don't like it, because i don't know what is done. I've tried these methods: copying via thunar file ...