Linux gains flash filesystem
May 17, 2010 — by Eric Brown — from the LinuxDevices Archive — 1 viewsLinus Torvalds announced the release of Linux 2.6.34, which is notable for adding two filesystems: Ceph for distributed and cloud-based applications, and LogFS, which is optimized for flash-memory based devices. Other new features include a faster KVM virtualization driver based on Vhost.net technology, says LinuxPlanet.com.
Linux can never seem to get enough filesystems, it seems, as once again variations on this basic Linux plumbing lead the story on the new 2.6.34 Linux kernel release. (The last kernel release, 2.6.33 was somewhat out of the ordinary in that it did not introduce any major new filesystems.)
Announced yesterday by Linux creator and overseer Linus Torvalds (left), Linux 2.6.34 debuts Ceph and LogFS, says a story by Michael Kerner in LinuxPlanet. The LogFS filesystem targets devices with solid state drives (SSD) and other flash memory-based devices, writes Kerner.
According to the LogFS project site, LogFS is a scalable flash filesystem designed to replace JFFS2 (journaling flash filesystem 2 ). Both names are misnomers, says the project, as JFFS2 is actually a log-structured filesystem, while LogFS is primarily a journaling filesystem that also turned out to be log-structured as well. The chief real-world difference between them is that JFFS2 slows down with larger devices, while LogFS is scalable for both small and large devices, says the project.
Ceph, meanwhile, is a kernel client based on the Ceph project. This distributed file system is said to incorporate an Object Storage Device (OSD) system that distributes data across multiple storage nodes, thereby making it capable of managing petabytes of distributed storage.
According to the Ceph project, if any OSD fails, data is automatically re-replicated, a task that can be deployed over a large number of storage devices, thereby enabling recovery to proceed in parallel. Other distributed filesystems supported in the Linux kernel includes the Oracle Cluster Filesystem and Red Hat's GFS (Global Filesystem), says LinuxPlanet.
The story quotes Markus Rex, director of open platform solutions at Novell, as telling InternetNews.com that Ceph should prove important in enterprise and cloud environments running SUSE Linux. "When I look at the proliferation of storage and the sheer volume of terabytes that people have at their disposal, filesystem technology in Linux is on a very good track toward leveraging the space and capabilities of new storage technologies," Rex was quoted as saying.
Noting its involvement in the new kernel in a blog post today, the Ceph project was also quick to add that "Ceph is still experimental and is not yet ready for use in a production environment." Perhaps this is one reason that Tim Burke, VP of platform engineering at Red Hat, is taking a wait-and-see attitude in regard to Ceph.
"Cloud storage options continue to be highly active and evolving — a clear winner has not yet emerged," Burke was said to have told InternetNews.com. "It's still too early to tell how prominent a role Ceph will play."
Faster KVM
The KVM (Kernel-based Virtual Machine) virtualization hypervisor has been coming on strong in recent Linux kernels, as well as the latest Linux distributions, such as Red Hat Enterprise Linux (RHEL) 5.5 and this week's release of the RHEL clone CentOS 5.5. The new Vhost-net technology in Linux 2.6.34 is intended to reduce virtualization overhead whenever possible, says LinuxPlanet.
According to the Linux-kvm.org page, Vhost.net is a kernel-level backend for virtio, the main platform for I/O virtualization in KVM. Vhost.net reduces virtualization overhead for virtio by removing up to four system calls per packet on data path, without guest changes, says the Vhost.net project. The intended result: faster performance for I/O-intensive KVM virtualization sessions.
Red Hat has worked closely with the Linux kernel team on Vhost.net, which it hopes to implement in RHEL 6, Burke was said to have told InternetNews.com.
According to a report on Linux 2.6.34 today by OSNews, the Vhost.net technology is said to provide "almost-native" KVM network performance. Other notable new features in the 2.6.34 release according to OSNews include a new VMware driver, a "kprobes jump" optimization for dynamic probes, new perf features, support for GPU switching, as well as improvements to the Btrfs filesystem.
In addition, the new release is said to provide RCU lockdep, support for Generalized TTL Security Mechanism and private VLAN proxy arp support, as well as asynchronous suspend/resume features.
Availability
Linus Torvalds' announcement of Linux 2.6.34 may be found here. The LinuxPlanet report on the release should be here. The OSNews story on the release should be here.
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.