This article is about the Linux zram feature, previously known as "compcache". For the dynamic random-access memory technology Z-RAM, see Z-RAM.
zram is a module of the Linux kernel, previously called "compcache". zram increases performance by avoiding paging on disk and instead uses a compressed block device in RAM in which paging takes place until it is necessary to use the swap space on the hard disk drive. Since using RAM is an alternative way to provide swapping on RAM, zram allows Linux to make more use of RAM when swapping/paging is required, especially on older computers with less RAM installed.
Despite the cost of RAM being relatively low (as of February 2014[update]), zram still offers advantages for embedded devices, netbooks and similar low-end hardware devices. Such devices usually use flash-based storage which has a limited lifespan due to its nature, so avoiding its usage for providing swap space prevents it from wearing out quickly. Also, using zram results in a significantly reduced I/O for Linux systems that require swapping.