Farkas Levente wrote: > I'm just read > http://www.hpl.hp.com/techreports/2002/HPL-2002-352.pdf > may be it's worth to read. an intersting thing about performance (XP, > their user-space raid and than comes kernel raid). Any comments from md developers? This is from the abstract: The paper contains preliminary results from an investigation comparing Linux and WindowsXP disk I/O using kernel-based software RAID on identical hardware. WindowsXP performance is shown to be substantially superior to Linux performance, for reasons not currently understood. And the meat of the report: 5.5. Direct comparison Of crucial interest is the direct comparison between WindowsXP, the kernel-based Linux software RAID implementation, and the userlevel software RAID implementation. From Figure 8 it can be seen that csraid generally outperforms the kernel-based RAID driver, and its performance is far more stable, particularly for large requests. Also, the WindowsXP RAID driver is astonishingly good, even compared to JBOD, with JBOD?s performing better for request sizes smaller than 4MB and WindowsXP performing better at the larger sizes. csraid?s performance is generally less than WindowsXP, but overall the loss is not catastrophic, and is likely sufficient for the most purposes. Figure 8 shows that XP's RAID can be 60+% faster than md at writing, and up to 100% faster at reading (at request size 7MB, which is rather a blip). Any inital thoughts on this report? Has the performance changed substantially since? The distro was Mandrake 8.2, the kernel 2.4.18-6mdk. Any comments on the methodology or conclusions? -- Illtud Daniel illtud.daniel@llgc.org.uk Uwch Ddadansoddwr Systemau Senior Systems Analyst Llyfrgell Genedlaethol Cymru National Library of Wales Yn siarad drosof fy hun, nid LlGC - Speaking personally, not for NLW - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
