Yes, you're correct ... however, the idea in OpenGFS was to not rely on pool, but to allow other "generic" volume managers to be used instead. -- Ben -- Opinions are mine, not Intel's > -----Original Message----- > From: linux-cluster-bounces@xxxxxxxxxx > [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Erling Nygaard > Sent: Wednesday, July 07, 2004 12:21 PM > To: Discussion of clustering software components including GFS > Subject: Re: [Linux-cluster] Gfs_data vs gfs_journal > > Ben > > You can indeed have external journals with GFS. > > As Mike was saying, you can specify a subpool with type "gfs_journal". > And since you easily can specify what device the subpool is > on you decide > where the journal is. > > This feature has been in GFS since 'a looong time ago' and > unless there > have been changes to this in OpenGFS this feature works in > the same way in > all versions of GFS :) > > As Mike pointed out, this was originally done in case of Solid State > Disks, where having the journals on the SSD could prove > speedup. Due to > lack of SSDs this has never really been tested much... > > > Erling > > > > On Wed, Jul 07, 2004 at 08:16:59AM -0700, Cahill, Ben M wrote: > > Oops, based on Michael's response, I realized that mine might be not > > quite right. Both data and journal *space* are necessary, but the > > journals can be created, by default, within the filesystem > device, with > > no need for gfs_journal entry in config file. > > > > BTW, OpenGFS has supported external journals for over a year at this > > point ... would this be a useful feature for GFS? > > > > -- Ben -- > > > > Opinions are mine, not Intel's > > > > > -----Original Message----- > > > From: linux-cluster-bounces@xxxxxxxxxx > > > [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of > Cahill, Ben M > > > Sent: Wednesday, July 07, 2004 11:07 AM > > > To: linux-cluster@xxxxxxxxxx > > > Subject: RE: [Linux-cluster] Gfs_data vs gfs_journal > > > > > > They are both necessary. > > > > > > gfs_data is the device/partition for filesystem data > (i.e. files and > > > on-disk metadata). > > > > > > Each node in the cluster also needs a separate journal > > > device/partition > > > in which to redundantly record metadata, to enable the > filesystem to > > > recover gracefully from node failure/crash. > > > > > > There's some documentation about this in the OpenGFS project: > > > > > > opengfs.sourceforge.net/docs.php > > > > > > CAUTION: OpenGFS is *not* the same as current RedHat > GFS; many things > > > (e.g. lock protocols) are different ... but the basic idea is > > > the same. > > > See WHATIS-OpenGFS, and HOWTO-generic, just to see if > they help you > > > understand. But remember to rely on current RedHat GFS docs > > > for current > > > installation, components, and capabilities info. > > > > > > -- Ben -- > > > > > > Opinions are mine, not Intel's > > > > > > > -----Original Message----- > > > > From: linux-cluster-bounces@xxxxxxxxxx > > > > [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of > > > Richard Mayhew > > > > Sent: Wednesday, July 07, 2004 6:24 AM > > > > To: Discussion of clustering software components including GFS > > > > Subject: [Linux-cluster] Gfs_data vs gfs_journal > > > > > > > > Hi, > > > > > > > > Could some one explain or point me in the right direction in the > > > > differences between gfs_data and gfs_journal in the pool > > > config file. > > > > > > > > Which is the better option, and why? > > > > > > > > Thanks > > > > Richard. > > > > > > > > -- > > > > > > > > Linux-cluster@xxxxxxxxxx > > > > http://www.redhat.com/mailman/listinfo/linux-cluster > > > > > > > > > > > > > > -- > > > > > > Linux-cluster@xxxxxxxxxx > > > http://www.redhat.com/mailman/listinfo/linux-cluster > > > > > > > > > > -- > > > > Linux-cluster@xxxxxxxxxx > > http://www.redhat.com/mailman/listinfo/linux-cluster > > -- > Erling Nygaard > nygaard@xxxxxxxxxx > > Red Hat Inc > > -- > > Linux-cluster@xxxxxxxxxx > http://www.redhat.com/mailman/listinfo/linux-cluster > >
