From mboxrd@z Thu Jan 1 00:00:00 1970 From: SandeepKsinha Subject: Re: Change Chunk Size on Array? Date: Wed, 13 May 2009 10:23:35 +0530 Message-ID: <37d33d830905122153j5c38cddby616863e026cd241e@mail.gmail.com> References: <16137381.post@talk.nabble.com> <23514897.post@talk.nabble.com> <18954.20603.952706.467047@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <18954.20603.952706.467047@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Wed, May 13, 2009 at 10:15 AM, Neil Brown wrote: > On Tuesday May 12, sandeepksinha@gmail.com wrote: >> >> >> >> crshman wrote: >> > >> > Hello All, >> > >> > I wanted to know if it were possible to change the chunk size on a= n array >> > after it has been created. I have a software raid 5 comprised of 7= drives >> > with a chunk size of 64k. I wanted to up that to 1024k, would this= be >> > possible without losing any data? This isn't mission critical so i= t is ok >> > if i need to stop the array first, however I'd rather not lose any= data. >> > >> It is possible to change the chunksize but for the same you would ne= ed to >> offline your array. > > Is it? =A0How? > That was all that I could read from" RAID on Linux" by Derek Vadala, Pa= ge 118. It mentions that this could be achieved by offlining the array and using "raidreconf". He also mention chances of data loss and also the caveats of "raidrecon= f". > Online changing of chunk size for raid5 is very close to being > implemented. > All the kernel side support will be in 2.6.30. > I just need to spend some time getting mdadm to make it work. > Because data is being rearranged in-place, and because you don't want > to lose everything if your systems crashes, mdadm will have to work i= n > tandem with the kernel making a backup copy of a section of the array= , > allowing the kernel to reshape that section, and then moving on to th= e > next section. =A0It will be slow, but it will be reliable. > > NeilBrown > --=20 Regards, Sandeep. =09 =93To learn is to change. Education is a process that changes the learn= er.=94 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html