Well, now you've gone and opened up a whole new can of worms. :-) It is absolutely not the case that hardware RAID has across the board lower risk of data corruption, with or without caching. Caching usually increases speed, as you say.
Take a look at this article if you want to be scared about data corruption, even when using hardware RAID: http://storagemojo.com/2007/09/19/cerns-data-corruption-research/ Theoretically, ZFS has much better data integrity than other file systems / volume managers / RAID controllers because it checksums all data and all metadata, all the time. Nothing else (that I know of) does this. --Peter Blog: http://pbgalvin.wordpress.com On 2/27/08 12:08 PM, "Edward Ned Harvey" <[EMAIL PROTECTED]> wrote: >> RAID can be implemented in hardware or software. Can't speak to all >> hardware >> RAID controllers, but NetApp does RAIDDP, and ZFS has RAIDZ2, both of >> which >> are double-parity-disk RAID (i.e. Survive 2 disk failures rather than >> 1). > > This is very interesting. Is there any hardware controller that does the > same? > > I do think there's value in the hardware raid controller. Guess what, we've > all seen sometimes kernel crashes. And if we had enabled write caching, > we'd encounter FS corruption for whatever had not yet been written. But > with a caching raid card, with battery backup, you get all the performance > benefit (if not more) with lower risk of data corruption. > > The performance difference is most apparent when working on a zillion small > files. The most dramatic difference I've seen is when formatting the FS, > because of course, that's such a sparse write operation. To format 1Tb on > my Dell, ext3, it took 40 minutes without write cache enabled on the raid > card, and it took 40 seconds with the write cache enabled. > > _______________________________________________ > bblisa mailing list > [email protected] > http://www.bblisa.org/mailman/listinfo/bblisa _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa
