Questions tagged [caching]
The caching tag has no usage guidance.
34
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51
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Temporarily disable bcache read caching to run a scrub
I use btrfs atop of bcache. It caches small reads and that works great.
When running a scrub of the btrfs however, I'd like those reads to go through to the backing devices because their contents are ...
- 697
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62
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Is there a seamless way to cache the file table of an HDD to prevent unnecessary spin ups?
I'd like to be able to browse the file system of my external HDD without having it spin up. Is there an easy way to cache its file table in a way that allows me to use normal tools like Caja/Gnome ...
- 11
2
votes
1
answer
412
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PKCS#11 provider in OpenSSH: Is it possible to cache PIN?
I use a RSA key on a smartcard with an OpenSSH client. The smartcard is read by a smartcard reader with a pinpad. The key is protected with a PIN.
Is it possible to cache the PIN somehow? I don't ...
- 897
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107
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Does cygserver improve Cygwin performance? If so, with what tasks?
I've read that cygserver can improve performance in some circumstances but I'm not really clear on how - or on how to know whether it's applicable to our use case.
Can anyone provide any insights?
- 271
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76
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Is there any OS-level caching for bare block devices? If so, how do I bypass it?
If I read and write directly to a block device (e.g. /dev/sda1), is there any OS-level caching involved on Linux? If so, how do I bypass it, is opening with O_DIRECT enough?
I'm writing a simple ...
- 1,211
1
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1
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689
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Is it possible to disable page caching on Ubuntu?
I am running an application on Ubuntu 20.04 which requires me to clear the page cache everytime I run it. Currently, I just run echo 1 | sudo tee /proc/sys/vm/drop_caches everytime before I run the ...
1
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1
answer
3k
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What exactly is being cached when opening/querying a SQLite database
I was asked to improve existing code to query SQLite databases. The original code made a lot of separate calls to the database and filtered the results in Python. Instead, I opted to re-write the ...
- 183
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52
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Using excess video memory for disk caching?
On newer Ryzen 5000-based laptops, the integrated graphics controller always gets at least 1GB of shared video memory. In the BIOS settings, 1GB is the minimum. For people who don't need 1GB for video ...
- 1
1
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671
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gnome-disks write caching
in RHEL/CentOS 7.9 anyway, when running gnome-disks which is under the Applications-Utilities-Disks menu, for a recognized SSD it offers the enabling of write-cache.
I would like to know what ...
- 7,423
2
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1
answer
694
views
Optimize adding extra packages to the USB-media for alpine linux offline install?
We would like to make an automated installer for Alpine Linux for running our own application on an embedded x86 pc. Our application setup requires packages not present on the downloadable media and ...
- 1,053
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94
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how to get Linux to automatically release old pagecache pages?
Ever since upgrading to Linux kernel 5.8 and later, I've been having problems with my system freezing up from running out of RAM, and it's all going to the pagecache.
I have a program that reorganizes ...
- 11
1
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338
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Is it possible to avoid trashing hard disk while using /tmp as a RAM device?
Origin
I need to implement some features to my GDB helper scripts but I have to stick with an older version of GDB (5.3, in this case). Since older versions lack so many features, I need to workaround ...
- 2,369
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292
views
How can I combine LVM cache and writecache?
Can I attach both a cache (in modus Writethrough) as well as a writecache to a logical volume in LVM? If yes, how?
I am well able to attach a "normal" cache. But when trying to also add a ...
- 1,929
1
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135
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Apache configuration so images are cached for a long time
I'm asking here since no matter what I try I keep noticing images keep being reloaded after a while. Basically I want images to be cached for 11 months, but if anything they seem to be cached for ...
- 190
2
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0
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73
views
Automatically store based on file size - linux - bcache?
Hoping to get answers to this on Debian based distros:
When saving a file, from any program, I'd wish to know if it is possible for the OS to automatically save based on file size. For example, ...
- 21
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1
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1k
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Testing bcache with raspberry pi 4 on ubuntu
I was testing bache on raspberry pi 4 with ubuntu. The reason I choose ubuntu that I found standard raspbian got some issues with bcache as kernel module not properly loaded. I tried to troubleshoot ...
- 304
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552
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Why are RAM cached NFS file contents corrupted?
We have an NFS server and several clients (Ubuntu 18.04). Sometimes (rarely) a client sees corrupted data after a file was changed from another client. The server and all other clients see the file ...
- 501
2
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1
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2k
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Configuring Stub Resolver in RHEL 8: systemd-resolved not caching DNS queries
In RHEL 8, systemctl list-unit-files|grep resolved reports that systemd-resolved is both present and running by default. However, systemd-resolve --statistics shows no name:ip mappings are being ...
- 2,614
2
votes
2
answers
8k
views
systemctl enable tmp.mount
Consider the practice of mounting the /tmp directory on a tmpfs memory based filesystem, as can be done with:
systemctl enable tmp.mount
And consider the following:
one justification: The use of ...
- 7,423
3
votes
0
answers
491
views
Using a LVM Raid0 as a LVM Cache for / on Linux Mint
I have a pair of solid state drives (/dev/sda and /dev/sdc) and a hard drive (/dev/sdb). I would like to install the system to the hard drive, collect the SSD's into a Raid-0, and divide up that Raid-...
4
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2
answers
8k
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Why Linux does not clean up disk caches and swap automatically?
For example, when I archive a few gigs of files (using tar), Linux uses quite a lot of disk caching (and some swap) but never cleans it up when the operation has completed. As a result, because there'...
- 263
1
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2
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80
views
Load program binaries at boot
I've written some utility scripts for my linux system. The problem is that the first invocation of programs lag a bit, I suppose it's the disk delay. Is there a way I can cache these scripts without ...
- 1,401
7
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answers
5k
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Using dd on Mac OS: conv=fsync equivalent?
I'm running an experiment where I benchmark the speed of reading and writing with and without caching. On Linux, using 'conv=fsync' as an operand makes sure that the output file is entirely physically ...
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6
votes
1
answer
2k
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Key passphrases and sshd -- cached authentication?
Asking a more precise question:
It appears that I can complete an rsync-over-ssh, using a key that requires a passphrase, without entering the passphrase. For example, I can run the rsync from the ...
- 403
0
votes
1
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173
views
Displaying replacement strategy of Level 1 Cache
I want to find out which replacement strategy my Level 1 Cache (8-way Set-associative) is using. Where can I find this information in Linux? Running dmidecode -t cache gives me all kinds of ...
- 183
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1
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79
views
Is it possible to give caching preferences to the filesystem?
I have a directory (/srv/data) with a large number (20,000,000) with a number of small (4-40KB) files. These files are all located in subdirectories of /srv/data, where the concatenation of the ...
- 449
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739
views
dd command 4M block size - buff cache
dd if=/dev/urandom of=file1 bs=4M count=100
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ ---timestamp---
r b swpd free buff cache si so bi bo ...
- 21
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1
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214
views
Is there disk-level caching in Solaris 11?
I have an iSCSI disk at /dev/rdsk/c5t6d0
I have made a partition (slice with UEFI label) at: /dev/rdsk/c5t6d0s0
Now I write some data to the slice:
echo "...
- 1,191
5
votes
1
answer
3k
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Use SWAP as disk cache in Linux
I am using different kind of disks on my server. Is it possible to use faster disk as SWAP and ask Linux to use it as Disk cache
As I understand Linux use SWAP only for application data not disk ...
- 81
6
votes
0
answers
890
views
bcache: writeback strategy
I'm using bcache with about 1 TByte of SSD caching for about 40 TByte of data. With writeback and 10% configured for bcache, about 100 GByte of dirty data exist only on the caching devices.
I like ...
- 417
0
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1
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2k
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Enable sssd caching and linux to honor that cache on CentOS 5
I wanted to enable sssd caching on CentOs and not to use nscd caching, because sssd itself is giving that option. However, authconfig is not giving the option for --enablecachecreds even on the ...
- 431
21
votes
2
answers
13k
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How can I safely create and access temp files from shell scripts?
I've read that redirecting output to a fixed name file in /tmp can be a security risk, because if an attacker (or malcontent) notices that a file /tmp/tmpfileformyscript.tmp is created when I run my ...
- 36.8k
4
votes
2
answers
2k
views
HTTP response header for Cache-Control not working in Apache httpd
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
...
- 89
3
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1
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94
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Is it possible to set mod_expires directives dependent on REMOTE_ADDR?
Basically I have a bunch of mod_expires directives in my httpd.conf like so:
ExpiresByType text/html "access plus 1 hour"
I realize that ultimately, the user's browser determines how long to hold ...
- 16.9k