From: Dexuan Cui Subject: RE: Can one file system be R/W mounted multiple times in Linux? Date: Fri, 9 Jan 2015 06:48:54 +0000 Message-ID: References: <20150109035123.GG22149@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Cc: Al Viro , "linux-fsdevel@vger.kernel.org" , linux-ext4 , "stefanha@redhat.com" To: Eric Sandeen Return-path: In-Reply-To: Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org > -----Original Message----- > From: Eric Sandeen [mailto:esandeen@redhat.com] > Sent: Friday, January 9, 2015 14:05 PM > To: Dexuan Cui > Cc: Al Viro; linux-fsdevel@vger.kernel.org; linux-ext4; stefanha@redhat.com > Subject: Re: Can one file system be R/W mounted multiple times in Linux? > > On Jan 8, 2015, at 10:59 PM, Dexuan Cui wrote: > > >> -----Original Message----- > >> From: Al Viro [mailto:viro@ftp.linux.org.uk] On Behalf Of Al Viro > >> Sent: Friday, January 9, 2015 11:51 AM > >> To: Dexuan Cui > >> Cc: linux-fsdevel@vger.kernel.org; 'linux-ext4'; stefanha@redhat.com > >> Subject: Re: Can one file system be R/W mounted multiple times in Linux? > >> > >>> On Fri, Jan 09, 2015 at 03:44:16AM +0000, Dexuan Cui wrote: > >>> The 'mount' utility allows me to mount 1 file systems multiple times at > >> different > >>> mount points, like "mount /dev/sdb1 /a; mount /dev/sdb1 /b". > >>> > >>> I tried to write from /a and /b at the same time and it seems everything is > OK > >>> and no data corruption happens. > >>> I tried only ext4 only. > >>> > >>> Can somebody please tell me if this usage is safe? > >> > >> Yes. > > > > Thanks for the confirmation! > > > > -- Dexuan > > But to be clear, just in case - this is completely different from, say, mounting the > same ext4 fs on two different nodes on a SAN, which is quite certainly not safe... > > -Eric Thank Eric for pointing this out! Can you please explain this? I didn't use SAN... Thanks, -- Dexuan