Recent MD enhancements
Posted Jan 26, 2006 14:18 UTC (Thu) by brugolsky
Parent article: MD / DM
Jon, there are lots of other important MD patches that have gone in recently that probably deserve an article of their own. In particular, the capability to rewrite a stripe when a read error occurs means that MD can often recover from an error, rather than kick the drive out of the array. One can also proactively do a background scan, like many hardware RAID controllers. Additionally, bitmapped-based intent logging allows for faster resyncs, when required. Given the nature of today's huge drives, these changes greatly increase the utility of MD, as resyncing a 500GB drive on a busy server can take days if it is only resyncing at say, 5MB/s, and runs the risk of exposing a latent error on another drive.
These and other recent changes have brought MD robustness and usability much closer to that offered by expensive hardware RAID implementations, while maintaining all of the flexibility, transparency, and performance that has long been the hallmark of Linux MD.
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