From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: External bitmap, questions Date: Sat, 19 Feb 2011 15:49:24 +1100 Message-ID: <20110219154924.2218c87c@notabene.brown> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mathias =?ISO-8859-1?B?QnVy6W4=?= Cc: Linux-RAID List-Id: linux-raid.ids On Sat, 19 Feb 2011 00:47:10 +0000 Mathias Bur=E9n wrote: > Hi, >=20 > >From the mdadm manual: >=20 > "-b, --bitmap=3D > [...] > Note: external bitmaps are only known to work on ext2 and ext3. > Storing bitmap files on other filesystems may result in serious > problems." >=20 > I was planning to store the external bitmap on an ext4 partition. Wil= l > this be a problem, or is the warning there because it hasn't been > tested enough but no problems found? External bitmaps use 'BMAP' to find where the file lives on the device = and then writes directly to the device - not through the filesystem. So as long as there is no tail-packing to block migration happening it = should work fine. I haven't looked inside ext4 but I am fairly confident that external bi= tmaps will work properly. NeilBrown -- 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