Archiv für den Monat: Oktober 2015

Debian: ZRam


All further development is now being done on the mainline Linux kernel; the code on this site is no longer maintained. Various wiki pages are retained here only for reference.
This project creates RAM based block device (named zram) which acts as swap disk. Pages swapped to this disk are compressed and stored in memory itself.
Compressing pages and keeping them in RAM virtually increases its capacity. This allows more applications to fit in given amount of memory.
The usual argument I get is – memory is so cheap so why bother with compression? So I list here some of the use cases. Rest depends on your imagination :)

Netbooks: Market is now getting flooded with these „lightweight laptops“. These are memory constrained but have CPU enough to drive on compressed memory (e.g. Cloudbook features 1.2 GHz processor!).

Virtualization: With compcache at hypervisor level, we can compress any part of guest memory transparently – this is true for any type of Guest OS (Linux, Windows etc.). This should allow running more number of VMs for given amount of total host memory.

Embedded Devices: Memory is scarce and adding more memory increases device cost. Also, flash storage suffers from wear-leveling issues, so its useful if we can avoid using them as swap device.

github: plitc/zramswap-enabler-debian

PS: Als Empfehlung – Kernel 3.16+