Zram: Difference between revisions

Latest revision as of 18:18, 4 June 2025

This page documents how to set up ZRAM in Alpine Linux. Zram can be used as an alternative to Swap partition.

Installation

Install the neccessary packages:

Configuration

For a basic ZRAM swap, configure ZRAM by editing the file /etc/conf.d/zram-init as follows:

Contents of /etc/conf.d/zram-init

load_on_start=yes
unload_on_stop=yes
num_devices=1
type0=swap
size0=8000

Advanced parameters can be found in the source repo.

Start services:

# rc-service zram-init start

View the ZRAM drive:

# cat /proc/swaps

Check Algorithms:

# cat /sys/block/zram0/comp_algorithm

Advanced setups may also add these parameters to /etc/sysctl.conf as follows:

Contents of /etc/sysctl.conf

vm.page-cluster=0
vm.extfrag_threshold=0
vm.swappiness=100

To ensure that service starts during next reboot:

# rc-update add zram-init

Troubleshooting

Check whether ZRAM's module is loaded:

# lsmod | grep zram

If not loaded, use modprobe to load it: (however, it should be automatically loaded if load_on_start=yes is in the configuration)

# modprobe zram

@@ Line 1: / Line 1: @@
-This page documents how to set up [https://docs.kernel.org/admin-guide/blockdev/zram.html ZRAM] in Alpine.
+This page documents how to set up [https://docs.kernel.org/admin-guide/blockdev/zram.html ZRAM] in Alpine Linux. Zram can be used as an alternative to [[Swap]] partition.
 == Installation ==
-Install the neccessary packages.
-{{Cmd|# apk add {{pkg|zram-init}}}}
+Install the neccessary packages:{{Cmd|# apk add {{pkg|zram-init}}}}
 == Configuration ==
-Make service start during next reboot.
-{{Cmd|# rc-update add zram-init}}
-Configure ZRAM SWAP:
+For a basic ZRAM swap, configure ZRAM by editing the file {{path|/etc/conf.d/zram-init}} as follows:{{Cat|/etc/conf.d/zram-init|<nowiki>load_on_start=yes
-{{Cmd|# vi /etc/conf.d/zram-init}}
+unload_on_stop=yes
+num_devices=1
+type0=swap
+size0=8000
+</nowiki>}}
+Advanced parameters can be found in the [https://github.com/vaeth/zram-init/blob/main/openrc/conf.d/zram-init source repo].
-For basic ZRAM swap:
+Start services:{{Cmd|# rc-service zram-init start}}
-# Update from num_devices=3 to num_devices=1
-# Change the size0=512 to the desired megabytes (same as available RAM or 8GB, whichever is less)
+View the ZRAM drive:{{Cmd|# cat /proc/swaps}}
-Start services:
+Check Algorithms:{{Cmd|# cat /sys/block/zram0/comp_algorithm}}
-{{Cmd|# rc-service zram-init start}}
-View the ZRAM drive
+Advanced setups may also add these parameters to {{path|/etc/sysctl.conf}} as follows:{{Cat|/etc/sysctl.conf|<nowiki>vm.page-cluster=0
-{{Cmd|# cat /proc/swaps}}
+vm.extfrag_threshold=0
+vm.swappiness=100</nowiki>}}
-Check Algorithms:
+To ensure that service starts during next reboot: {{Cmd|# rc-update add zram-init}}
-{{Cmd|# cat /sys/block/zram0/comp_algorithm}}
-Advanced setups may also add these parameters to /etc/sysctl.conf:
-* vm.page-cluster=0
-* vm.extfrag_threshold=0
-* vm.swappiness=100
-<!--
-Remove the remarks once content is added
 == Troubleshooting ==
--->
-== See Also ==
+Check whether ZRAM's module is loaded: {{Cmd|# lsmod &#124; grep zram}}
+If not loaded, use <code>modprobe</code> to load it: (however, it should be automatically loaded if <code>load_on_start=yes</code> is in the configuration) {{Cmd|# modprobe zram}}
+== See also ==
+* [https://github.com/vaeth/zram-init/blob/main/openrc/conf.d/zram-init sample zram-init file on official website]
 * [https://wiki.archlinux.org/title/Zram Zram in Arch Wiki]
 * [https://en.wikipedia.org/wiki/zram Zram in Wikipedia]
 [[Category:System Administration‏‎]]
-[[Category:Storage‏‎‏‎]]
 [[Category:Storage‏‎‏‎]]
 [[Category:Kernel]]
-[[Category:Filesystems‎]]