On Sun, Jun 04, 2006 at 10:18:22PM +0800, Eric Zhang wrote: > Pvfs runs smoothly and everything is OK. But I want to know what > will happen if any disk damaged, I mean, If one of these disks > failed, all data will lose? How pvfs2 deals with this situation?
PVFS2 deals with this situation the same way a raid-0 array would deal with it: there would be a loss of data, and you'd have to restore from backups. The common solution is to deploy raid 1 on each pvfs2 storage node. then pvfs2 can sustain one disk failure per storage node. > have read the "pvfs-ha.pdf" but this kind of solution based on my > cluster nodes have redundance disks that I don't have. Does pvfs > support redundance storage policy? Just like RAID 1, when data > arrives, we write it to two nodes and at the same time, we write > another copy of data to the other two nodes. Thanks, any > suggestions will be appreciated. If you don't want to pay for additional hardware and you don't want to pay for enough storage to back up pvfs2, then you'll have to treat PVFS2 as it was intended: as a fast scratch space for applications. Commonly, data is staged onto pvfs2 before running an IO-intensive application and shipped off of to storage which is presumably backed-up. Software-based redundancy is a lot harder to solve at the file-system layer than it is at the device layer. Specifically, it's a real challenge to in effect write two copies of data without cutting overall write performance in half. Several research efforts are ongoing to deliver software redundancy with high performance, but these efforts are still in early stages. I hope this explanation is clear. There is definitely a lot of demand for software-based reduncancy, and we're working on it. ==rob -- Rob Latham Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF Argonne National Labs, IL USA B29D F333 664A 4280 315B _______________________________________________ Pvfs2-users mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
