Thanks, your explaination is very clearly. I am planning to install the second hard disk in each node of my cluster.
-----Original Message----- >From: "Robert Latham"<[EMAIL PROTECTED]> >Sent: 2006-6-7 23:25:38 >To: "Eric Zhang"<[EMAIL PROTECTED]> >Cc: "[email protected]"<[email protected]> >Subject: Re: [Pvfs2-users] Pvfs2 failover policy >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
