Speeding up slow disks with SSD caching
Afterburner
Flash memory is fast but also expensive. Caching with Flash provides a way out: A smaller and cheaper SSD can speed up the disk.
Hard disks are inexpensive, and they have huge capacities, but they are also slow. Solid state disks (SSDs) are fast, but smaller and more expensive. If you combine the advantages of a hard disk with an SSD-based cache, you pick up a large performance gain at a reasonable cost.
An application generally does not want all the data at once; most of the data is in the state of being ignored most of the time. Caching lets you move the most frequently requested data to an exclusive, fast medium and leave the less-frequently accessed data on the cheaper but slower background medium.
The Linux environment has several tools that provide the necessary software to support hard-disk caching. Does it help to use an SSD-based flash drive as a cache for a traditional hard disk? We decided to find out. This article explores the possibilities for caching with the Linux caching tools Enhance IO and dm-cache. If you are new to the topic of caching, and you would like some additional information on choices you might have to make, see the boxes titled "A Little Cache Theory" and "How Flash Works."
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
United Nations Open Source Portal Goes Live
A new open source portal seeks to coordinate and scale open source efforts across the United Nations system.
-
KDE Linux Drops AUR
KDE Linux developers have dropped the Arch User Repository from the build pipeline due to security concerns; other distributions should consider doing the same.
-
California May Exempt Linux from Its Age-Verification Law
After backlash from the Linux community, California may be backing off on its promise to force all operating systems to verify age, but one platform may still have to comply.
-
Another Logic Bug Found in Linux Kernel
Qualys has discovered a vulnerability in the Linux kernel that can be used to elevate standard user privileges.
-
Ubuntu Core 26 Offers Game-Changing Enterprise Features
Ubuntu Core 26 could be a game-changer for organizations looking for increased security and reliability.
-
AI Flooding the Linux Kernel Security Mailing List
AI is giving Linus Torvalds a headache, but not in the way you might think.
-
Top Priorities for Open Source Pros Seeking a New Job
Professional fulfillment tops the list, according to LPI report.
-
Container-Based Fedora Hummingbird Designed for Agent-First Builders
Fedora Hummingbird brings the same approach to the host OS as it does to containers to level up security.
-
Linux kernel Developers Considering a Kill Switch
With the rise of Linux vulnerabilities, the kernel developers are now considering adding a component that could help temporarily mitigate against them… in the form of a kill switch.
-
Fedora 44 Now Gaming Ready
The latest version of Fedora has been released with gaming support.