On Fri, May 15, 2009 at 9:38 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > SandeepKsinha wrote: >> Hi all, >> >> Looks like we have the same code for RAID 4 and RAID 5, I could see >> the same make_request for both. >> >> Can someone point me in the code, where exactly we differentiate >> between these two. i.e updating checksum block, etc. >> > > RAID 4 is really nothing but a block layout algorithm for RAID 5 (which > has four more block layout algorithms.) RAID 6 contains all five under > one "level". > RAID 4 vs RAID 5 Actually debatable. They have their own pros and cons and especially where you don't consider the physical properties of disk. Addition of new disk, differences in speed of disks, etc.. create bottlenecks especially in case of RAID5. Except hot spot issue with RAID 4, I find it better than all others. Also, most of the proprietary solutions from IBM, Adaptec and NetApp suggest RAID4 as compared to others. No offenses please, this is just an opinion. > -hpa > > -- > H. Peter Anvin, Intel Open Source Technology Center > I work for Intel. I don't speak on their behalf. > > -- Regards, Sandeep. “To learn is to change. Education is a process that changes the learner.” -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
