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* Press Release [Reference Material] April 05, 2005

VA Linux is Ready to Offer 'VA Quest', A Complete Failure Analysis Solution Service for the Linux Kernel

-- The Power of VA Linux's Highly Skilled Linux Kernel Engineers is Now Available for You on a Full-Time Basis, to Tackle Your Own Problem on Mission-Critical Systems --

VA Linux's past achievements in the Linux kernel development

VA Linux contributes to the Linux kernel development in many fields. The most notable three are: Zerocopy NFS, Memory hotplug and Mini Kernel Dump. Zerocopy NFS has already been incorporated into the latest Linux kernel (2.6 series). Memory hotplug is under active discussion in the international community of Linux kernel developers, and will be incorporated into the next stable release. Mini Kernel Dump has been developed by VA Linux with NTT Data, and released as an open source software on October 13, 2004.

Zerocopy NFS

Under Linux kernel 2.4, when the NFS server processes Read requests, memory is copied from the page cache to the NFS send buffer. This is then copied to the socket buffer within the layered protocol and the network driver carries out a send process.

This issue has been improved Under Linux kernel 2.6 so that the page used in the page cache is sent directly to the layered protocol and, when possible, is also sent as is to the network driver as well. Through this, obviously, overhead created by wasteful copy processes is eliminated and the amount of useful data that is purged from the processor's internal memory cache is eliminated.

Hirokazu Takahashi, head technology officer of VA Linux, was responsible for this implementation under the Linux kernel.

Linux memory hotplug

The Memory hotplug is a function that actively adds and removes memory modules while the target system is running. This is particularly needed in enterprise systems, where a high degree of open availability is needed.

The Memory hotplug function differs from device-based hotplugs and there are still many issues being faced before its implementation is fully realized.

Architecturally speaking, one point to pay specific attention to is for creating conditions in which it is possible to continue to use important data that has been allocated to memory modules even after removal of a given memory module has transpired.

Mini Kernel Dump

Mini Kernel Dump is a crash dump function which automatically sends all internal information to an external recording device at the moment a failure occurs on Linux-based systems. When compared with Unix-based enterprise systems, determining the cause of a failure on Linux systems has been considered a major weakness. This tool aims to rectify this weak point.

Current Linux systems offer such failure analysis features as LKCD, netdump, and diskdump. However, all of those existing solutions have a major drawback -- they need some Linux device drivers to put their information out, thus they actually rely on the very Linux kernel they are running on and monitoring. This makes it extremely hard to get needed information under tough situations when even the Linux kernel itself is unstable and unreliable. Mini Kernel Dump overcomes this difficulty by using another small Linux kernel dedicated only to get dumped information. Therefore, Mini Kernel Dump does not depend on the target Linux Kernel. Besides, Mini Kernel Dump does not require too much modification on the target Linux kernel, thus the expected cost for introducing Mini Kernel Dump solution is very low. Also, Mini Kernel Dump should work under any hardware configuration since no modification for device drivers is needed.