Questions tagged [zram]
The zram tag has no usage guidance.
36
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Arch: Recreate Swap Partition?
I'm running arch, installed with archinstall.
I read that arch uses zram for swapping, not disk. Also read somewhere that zram doesn't use disk for swap, so i don't need a swap partition. (I don't get ...
- 361
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0
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57
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Selectively exclude paths or filesystems from Linux disk read cache
The Linux kernel uses unused RAM for disk read caching. This is generally a good idea. But is there a mechanism to selectively exclude certain paths or mounted filesystems from this cache?
ZFS for ...
- 351
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1
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1k
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PopOS 22.04 - Swappiness ZRAM value, size
How to change the "zram" size in PopOS 22.04? I did not create a ram partition, I was automatically added zram, which is 16.6 gb. It has a swappiness of 180, I want to change it to swappines ...
1
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1
answer
200
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Any way to create zram disk (not swap) during boot time except via script?
https://askubuntu.com/questions/130374/ramdisk-compressed-writeable-no-swap
Gives script to make zram disk (load module, set parameter, format block device, mount). Is there any way to have same ...
- 947
1
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0
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119
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initramfs on zram
I use a minimal initramfs as my root filesystem which I load from the network. Since the initramfs is just there to get the system started (and I have no other rootfs) I'd like it to take up as little ...
- 151
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1
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394
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Can't mount zram device on /tmp (Booting problem)
I have a simple script that creates a zram device and formats it to ext4 and finally, it mounts zram on /tmp.
#!/bin/bash
# create zram with size 1.5G
# $zram_dev is created device path (eg. /dev/...
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0
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88
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How to limit swap usage without using sysctl or resizing the partition?
There is the following scenario: I have an HDD disk that uses LVM and I cannot resize the partitions in it, in this disk, there is a swap partition that is 10gb. I also use zram apart from disk based ...
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3
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1k
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Does swap on zram free backing pages when pages are unswapped from it?
Imagine a scenario where 2GiB is swapped out to zram and compresses down to 1GiB.
Once the memory pressure is alleviated and the 2GiB gradually become unswapped, does Linux free the 1GiB of pages that ...
- 648
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1
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604
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My RAM usage never goes over 75% when system is lagging and under heavy load
Linux matrix 5.15.2-xanmod1-1 #1 SMP Wed, 17 Nov 2021 02:36:25 +0000 x86_64 GNU/Linux
NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS
sda ...
- 139
1
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1
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509
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Explain Zram and Swap numbers
Ok, so there are really 2 questions here, why is my on disk swap being used? Is the compression of my swap really this good? It seems pretty unlikely, but it's also possible it is because it's memory ...
- 58.5k
3
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0
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458
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How much percentage should zram take?
I'm setting up zram on my server, let's say I have 4GB ram, should zram take 3.5G or 1G or something in between? What trade off will I have when going to the extremes?
And, for example I have a single ...
- 131
1
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1
answer
852
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zramswapon failed: Operation not permitted
When I try to enable the zram service on a machine with 32 cores, it fails when the number of devices is greater than 26.
Also, I do not see any configuration file, only zramctl utility with no ...
- 13
2
votes
0
answers
135
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"Preempting" less-used pages in high priority swap to lower priority swap
Let's say I've got two swap partitions on my Linux machine. One is zram and a higher priority. The other is on disk and a lower priority. I prefer the zram swap because it's faster. As I understand it,...
- 153
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2
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665
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How to Enable ZRAM on PC?
I am trying to know how to enable ZRAM for my PC running Ubuntu. I have heard that the ZRAM is speeding up some laptop and PCs, so will the ZRAM help My PC too?
PC specs:
CPU: Intel Core 2 Duo E4500 (...
- 75
4
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1
answer
8k
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Why does zram occupy much more memory compared to its "compressed" value?
I set up zram and made extensive tests inside my Linux machines to measure that it really helps in my scenario. However, I'm very confused that zram seems to use up memory of the whole uncompressed ...
- 309
2
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1
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335
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Get % used of zram in script
I've got a script that collects various bits of system data and reports this via MQTT to a central local server. I recently implemented zram with priority over swap to see if this offers a performance ...
- 123
3
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1
answer
1k
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Using loopdev for zRAM writeback feature
Documentation states that zRAM writeback feature supports only swap partitions as it's backing_dev. But I've successfully used a swap file too, by attaching it to a loop device
losetup /dev/loop0 /...
- 767
1
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2
answers
1k
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Effect of enabling zswap on zram without any disk swap
I have set up a system that has 4 GB RAM with 1.5 GiB of zram. It also has zswap enabled. I don't have any swap partition on the secondary storage.
As I have noticed, the performance is good on my ...
- 2,009
1
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1
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1k
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After a heavy I/O load, and storing many things in Zram, used space is close to total in `free`
I do not think that this is Linux's disk cache. In htop, the memory bar is green (not orange for cache) and I removed the files stored in zram. No processes seem to be using a lot of memory.
The load ...
- 31
2
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1
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556
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How to change zram sector size?
I have cloned a disk into a sparse file that is about 80G but indeed requires only about 12G, even not compressed it fits on my memory, but in order to save some resources I want to use zram:
sudo ...
- 606
7
votes
1
answer
2k
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Make or force tmpfs to swap before the file cache
Consider the following scenario. You have a slow read-only media (e.g. write-protected Thumb Drive, CD/DVD, whatever) that you installed Linux on (not a Live CD per se, but a normal build), and use it ...
- 315
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1
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76
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compress a single file ... zram ? cloop?
We have a legacy centos 5.11 server;
filesystems are ext3, we cannot change.
Is it possible to have realtime compression on a single file (a giant log file) ?
zram : I cannot find it in the repos...
...
- 975
3
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1
answer
2k
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Is zstd for zram actually available in Linux 4.15?
I found zstd in /drivers/block/zram/zcomp.c, but I can't find anything zstd-related in /crypto.
So is zstd for zram actually available in Linux 4.15 or not?
- 953
8
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1
answer
5k
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Prevent zram LRU inversion with zswap and max_pool_percent = 100
The major disadvantage of using zram is LRU inversion:
older pages get into the higher-priority zram and quickly fill it, while newer pages are swapped in and out of the slower [...] swap
The ...
- 29.4k
0
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0
answers
427
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Why /sys/block/zram0/comp_algorithm not exist?
See zram kernel doc we know there should have /sys/block/zram0/comp_algorithm
Examples:
#show supported compression algorithms
cat /sys/block/zram0/comp_algorithm
lzo [lz4]
#...
- 391
12
votes
2
answers
5k
views
What is an alternative for zcache?
I want to use a high-speed swap device or zram as "page cache", so that page data can be dropped automatically when the system is out of memory.
Apparently, zcache has been discontinued. Is there an ...
- 361
3
votes
1
answer
1k
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systemd : write a .service daemon for setting up swap and fs in zram
I recently acquired a laptop with a ssd and in order not to weigh too much on the ssd (which I was told had a limited number of write cycles), I decided to write a systemd unit file for setting up a ...
- 976
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368
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Have I installed and started zram successfully?
On my Kubuntu 13.10 laptop, have installed zram by
sudo aptitude install zram-config
and the output of
swapon -s
Filename Type Size Used Priority
/...
- 2,569
4
votes
0
answers
901
views
How much RAM is there?
I'm trying to estimate how effective the zram kernel module is in case of my PC. I have a pretty old machine (7y) with the only 1 GiB of RAM.
I created two zram swaps (two core processor), 250MiB ...
- 10.4k
6
votes
2
answers
2k
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How do I determine ZCACHE works on my box?
I have an Marwell Kirkwood ARM-based NAS server Zyxel NSA 310. I compiled my own 3.8 kernel and enabled ZCACHE, but I still see 256 MB of RAM. I am not sure if GNU free utility should show extra ...
- 2,062
3
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0
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683
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zram swap instability
I use Mint 13 Maya with mainline kernel 3.6.3 for Ubuntu Quantal on my Asus P53E Notebook.
I use zram swap that comes with the package zram-config.
I've noticed that using it the system to hangs at ...
- 5,531
18
votes
3
answers
15k
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What is the appropriate value of vm.swappiness when using zram?
I'm using zram on my computer as a compressed RAM-backed swap. When the system needs to swap something out, swapping it to a zram-backed swap file is more or less equivalent to compressing that data ...
- 5,408
4
votes
1
answer
2k
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How to fix zramswap error?
I installed zramswap-enabler on Ubuntu 11.10 using the ppa but when installing programs or running system upgrades I get this error:
Setting up zramswap-enabler (0.2.1-0~12~oneiric1) ...
start: Job ...
- 41
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1
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3k
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Zram does not start at start-up
I am using pinguyos 11.10. Pinguyos is a variant of Ubuntu 11.10.
I have installed zram like this:
sudo add-apt-repository ppa:shnatsel/zram
sudo apt-get update
sudo apt-get install zramswap-enabler
...
- 131
9
votes
2
answers
8k
views
Cleancache vs zram?
I have an old laptop here with only 512 MB of RAM. Since a few kernel releases, I am using zram to convert 256 MB of it to a compressed ramdisk which is then used as swap. This has proved to be very ...
- 303
12
votes
5
answers
27k
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How to set up properly zram and swap
I'm configuring & compiling new 3.0 kernel. One of the goodies I planned to use for some time (by patching) that was merged into 3.0 is zram.
Is it possible to set both hdd swap and zram swap so ...
- 16.6k