From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: repartitioning disks Date: Tue, 17 May 2011 20:39:44 +1000 Message-ID: <20110517203944.65d8114e@notabene.brown> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: CoolCold Cc: Linux RAID List-Id: linux-raid.ids On Tue, 17 May 2011 12:20:50 +0400 CoolCold wrote: > Wiki says: "Never NEVER never re-partition disks that are part of a > running RAID. If you must alter the partition table on a disk which is > a part of a RAID, stop the array first, then repartition. " - > https://raid.wiki.kernel.org/index.php/Tweaking,_tuning_and_troubleshooting#Pitfalls > > Is it really true for situations like - I have 2x1Tb drives, which are > already partitioned like /dev/sd{a,b}1 - 500mb, /boot & /dev/sd{a,b}2 > - 20gb, / and are assembled in RAID1 arrays md0 & md1 accordingly. So, > if I want to create one more RAID1 array , say md3 from the rest of > the drives. > So i take my cfdisk ,add new partition with some space 100-150mb from > the end, do write changes & partprobe the drives, then creating new > array. > > Is it bad? To be honest i'm doing this all the time and can't > understand how this gonna hurt md. Neil and/or others, please clarify > this. > > There shouldn't be any problem with that as long as you are careful (and if you aren't careful, there are plenty of other ways to destroy your data). I wasn't aware of partprobe. Just telling the kernel to reread the partition table won't work when a partition is in use. But partprobe seems to just tell the kernel about the partitions that have changed, using a different ioctl, and that seem to work. NeilBrown