Hi Neil, Thanks for your reply. As far as what I understood that when we apply the bitmap patch, for every write it will do 2 sync writes that is setting the dirty bit, writing intent log and one async write for clearing the dirty bit. Is it correct? If that is the case are there any patches available which can do collection of sync write in a queue and write a collection in single write request. For Eg: For 10 writes , we will have 10 + 1 sync writes + 10 async write. I mean to say , 10 sync writes for setting the dirty bits + 1 sync write for write intent log for all queued request in one write operation + 10 async write for clearing the dirty bit. So as we reducing the sync write request by using collections will it improve the performance and any patches available which follows this approach. Thanks and Regards Yogesh -----Original Message----- From: Neil Brown [mailto:neilb@xxxxxxx] Sent: Wednesday, March 22, 2006 3:36 PM To: Yogesh Pahilwan Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: Linux MD RAID5/6 bitmap patches On Wednesday March 22, pahilwan.yogesh@xxxxxxxxxxxxxxx wrote: > Hello, > > I want to know where I can get various MD RAID5/RAID6 bitmap patches for > linux kernel 2.6.15. 2.6.15 already includes support for bitmaps for MD raid5 and raid6 (And raid1). No patches needed. > I want to know what kind of performance optimization possible on bitmap > patches. I also want to know are > there any patches available which provides performance optimizations using > bitmaps. Bitmaps optimise rebuild time after a crash, or after removing and re-adding a device. They do not improve normal read/write performance, and may well cause a small degradation in performance. NeilBrown - 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
