From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Lilley Subject: Re: Raid 5 --grow to fewer, larger drivers Date: Mon, 24 Nov 2008 18:28:16 +0000 Message-ID: <492AF240.9020608@redwax.co.uk> References: <492AA493.6080605@redwax.co.uk> <1f0f1a960811240621j619701aboc32c2da9765cd7a1@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1f0f1a960811240621j619701aboc32c2da9765cd7a1@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Twigathy Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids That is an interesting work around T, though it does have its own=20 issues, namely the need to take the data off-line for the time of the=20 copy over the network besides the hassle. I would be interested to know why there would be any greater=20 difficulty/risk in growing to fewer, larger disks than simply growing t= o=20 more disks of the same size. The problem is that if you have a number=20 of disks and need more space, you add another disk of the same size and= =20 lots of disks will eventually bite you on the bum, so being able to=20 consolidate in the way I set out would be a real bonus and nice and=20 straight forward (or maybe not!?) Regarding the risk factor during any array resync, I should hope we all= =20 have a precious data backed up anyway! Thanks for you =C2=A30.02 though :-) Alex Twigathy wrote: > In that situation, I think I'd be happier to hook all the disks up (I= f > not on the same machine, on two machines on the same [gigE] network, > make a new raid5 on the new set of disks, rsync stuff to the new arra= y > and then retire the old array (Swapping in the array you just > created)... messing around resizing disks for this job just sounds > like mess and risk to me! > > Just my =C2=A30.02 ;-) > > T > > 2008/11/24 Alex Lilley : > =20 >> Senario: raid5 with 4 x 120gb. >> >> aim: raid5 with 3 x 250gb >> >> 3 x 120gb disks replaced with 3 x 250gb, array has been rebuilt/resy= nc'd at >> original size. Can we remove the remaining 120gb drive and reshape t= he array >> over the remaining 3 drives using all the new space. >> >> I guessed --grow --raid-devices=3D3 --size-max would work but return= s "can >> change at most one of size, raiddisks, bitmap and layout" >> >> I then --failed and --remove the remaining 120gb drive and tried --g= row >> --raid-devices=3D3 but receive "Cannot reduce number of data disks (= yet)". >> >> I am therefore slightly stumped! >> >> Is this something that is actually possible or something that is pla= nned for >> because as the size of disk drives multiplies and the desire to keep= tabs of >> power usage increases it is likely that we will want to reduce the n= umber of >> disk, besides the obvious increased risk of failure introduced by ha= ving a >> greater number of drives. >> >> Regards >> >> Alex >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid= " in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> =20 > N=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BDr=EF=BF=BD=EF=BF=BDy=EF= =BF=BD=EF=BF=BD=EF=BF=BDb=EF=BF=BDX=EF=BF=BD=EF=BF=BD=C7=A7v=EF=BF=BD^=EF= =BF=BD)=DE=BA{.n=EF=BF=BD+=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD{=EF=BF=BD= =EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD{ay=EF=BF=BD=1D=CA=87=DA=99=EF=BF=BD= ,j=07=EF=BF=BD=EF=BF=BDf=EF=BF=BD=EF=BF=BD=EF=BF=BDh=EF=BF=BD=EF=BF=BD=EF= =BF=BDz=EF=BF=BD=1E=EF=BF=BDw=EF=BF=BD=EF=BF=BD=EF=BF=BD=0C=EF=BF=BD=EF= =BF=BD=EF=BF=BDj:+v=EF=BF=BD=EF=BF=BD=EF=BF=BDw=EF=BF=BDj=EF=BF=BDm=EF=BF= =BD=EF=BF=BD=EF=BF=BD=EF=BF=BD=07=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BDzZ= +=EF=BF=BD=EF=BF=BD=DD=A2j"=EF=BF=BD=EF=BF=BD!tml=3D -- 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