Questions tagged [cache]
cache is a component that stores data so future requests for that data can be served faster; the data stored in a cache might be the results of an earlier computation, or the duplicates of data stored elsewhere.
482 questions
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Spin down HDD on Server
I'm running Debian 13 (fresh install) and want to use specifically Nextcloud and Immich on docker on an SSD and 2 HDDs with 10TB for data (and the second for raid/snapraid or backups or similar).
For ...
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Is it a good idea to have inode size of 2048 bytes + inline_data on an ext4 filesystem?
I only recently "discovered" the inline_data feature of ext4, although it seems to have been around for 10+ years.
I ran a few statistics on various of my systems (desktop/notebook + server),...
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Why does the program that reads files still run very fast after clearing the page cache?
Test environment: Virtual Machine(Windows 11, VMware Workstation Pro), Ubuntu 22.04, mechanical hard drive.
Use the following command to generate 1GB of test data:
dd if=/dev/urandom of=test.data ...
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2
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How to prioritize SSD page cache eviction over HDD with slower speed?
I have a large slow HDD and a small fast SSD. This is about reads not RAID. My desktop grinds to a near-halt when switching back to Firefox or man pages after (re/un)-loading 12+ GiB of Linux kernel ...
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Alternate way to get the CPU cache size
I have a project where I need to get the size of the cache on my Linux machine. I don't know the linux distro, and the /etc/os-release file does not exist.
I only know the kernel and architecture:
...
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Share one SSD Cache across multiple volumes & storage pools on Synology NAS
I have a new Synology NAS with 2 storage pools, and I have one volume per pool.
I have added a single SSD to the NAS to serve as a cache, and was able to add it to the first storage pool. This is a ...
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Is there a FUSE-based caching solution for selective prefetching from a remote filesystem?
I am working with a remote parallel file system (CephFS), mounted at /mnt/mycephfs/, which contains a large dataset of small files (200 GB+). My application trains on these files, but reading directly ...
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Radix Tree vs Multi-level bitmap
The Linux kernel (at least before using XArrays as far as I'm aware, which to my knowledge are wrappers around Radix Trees anyway) uses radix trees in its address_space structs which every file has. ...
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Simulate slow disks in KVM to see effect of LVM cache in test setup
I'm setting up a Linux system in KVM (QEMU) to test the effect of adding a writeback LVM cache on a fast disk in front of a logical volume that resides on a set of very slow disks (a RAID1 LV). This ...
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Is it possible to get a higher memory buff/cache usage after writing a lot of data to the disk?
On an Apache server of my own, logging requests to files has been enabled using a custom Apache module.
The log files can reach several GB at the end of the day.
Using Nagios I have noticed memory ...
- 101
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What are the issues with timing sync and clearing cache?
Because there is a situation in my project where files cannot be saved to disk after being written, these two scripts have been added in the background. Will they have any impact on system performance?...
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How do I clear the cache without restarting my terminal?
I'm currently working on the POD supercomputer at UT Austin. Tech support for the supercomputer couldn't help me. There's a specific version of Python (3.9) I want to use in my Anaconda environment, ...
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Can't flush dns in kali linux in Virtualbox. It seems like neither of these are my dns client: systemd-resolve, resolvectl, nscd, dnsmasq
It seems like there are no dns clients(????).... but it's impossibile, it's just don't know how to find it.
$ sudo lsof -i :53 -S does not return anything.
systemctl restart nscd #or
systemd-resolve -...
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Can I invalidate the buffer cache of a block device?
I have a system which is a USB gadget. It exposes one of its partitions over USB using functionfs to allow the host to provide update files:
set -e
CONFIGFS_ROOT=/dev/gadget
CONFIGFS_DEV=$...
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How to empty name cache on FreeBSD?
The name cache on FreeBSD is responsible for caching file names and their vnodes. It also provides a special database for hashing the contents of large directories.
I would like to know how to empty ...
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How to clear all cache data of google-chrome by commands executed by a bash script?
In my lubuntu 18.04 distribution I have installed google-chrome version 114.
By a bash script, at every boots, Chrome is launched and connects to a specific URL. The URL is always the same, but ...
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Do we really need NSCD service running? What are the pros and cons?
We have a pretty mixed environment in terms of operating systems. Suse 12/15, Oracle Linux 6/7/8, Redhat 6/7/8 and a few others.
We've been using Active Directory authentication for some time.
For ...
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985
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cache smb mount on local hard drive
I have a smb mount on my linux server, but occasionally it loses connection, interrupting the software using the mounted directory. Is there a way to cache the smb mount on local disk?
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dentry/inode caching on multi-cpu machines / memory allocator configuration
While doing performance benchmarking on CPLEX, I ran across a strange issue. The details are posted in a blog: https://community.ibm.com/community/user/ai-datascience/blogs/xavier-nodet1/2021/07/08/...
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DDR memory errors or page cache corruption?
System: embedded, arm64 (4xCortexA53), 2GB LPDDR3, eMMC memory, Linux, kernel 5.4.17.
I am experiencing issues with random system crash, that in normal operation will happen every 2 days to every &...
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Clean ways to prime the kernel inode cache after boot?
Various answers on various StackExchange sites cover parts of this topic, but I did not see an exact match for this scenario. How can you identify every mounted standard filesystem, and traverse all ...
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Is rsync really a culprit for causing low memory on our VM?
In a VM of 16GB RAM, we are running rsync as a cron job(for every 10 minutes) on our production to sync GBs of folder from AWS EFS to local storage. After few days of running we found that the VM is ...
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Does logging into a shell session build a cache of executables on the path which never gets updated? [duplicate]
I notice that when I compile a custom build of a packaged program stored in /usr/bin eg /usr/bin/emacs, which emacs shows the already existing executable at /usr/bin/emacs instead /usr/local/bin/emacs,...
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Search [not install] without syncthing on Fedora
I would want to know if it is possible to search packages in Fedora (using dnf) without it having to sync anything previously.
I've read Fedora wiki about rpm, but I don't think I understand properly ...
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How to change the default BDI `max_ratio` and/or `min_ratio` for all devices?
I'm using a system with multiple storage devices with different write throughput. As explained in question Why were "USB-stick stall" problems reported in 2013? Why wasn't this problem ...
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