Sorry I got that, it's the file system integrity rather than "file/data" integrity. Thanks.
The other thing on my mind is: What would be the impact of adding more iscsi-target nodes to my LVM/GFS over SAN head? Does it going to make an impact over file seek time (file lookup read/write) for the client machine accessing a file over GFS? f.e. a file's data can be stored on iscsi-target nodeA , some data on iscsi-target nodeX. More disk space == more file lookup time? in case such thing does not happens then why? How does it works? Thanks and regards Anuj Singh On Wed, Apr 30, 2008 at 2:37 PM, अनुज Anuj Singh <[EMAIL PROTECTED]> wrote: > Hi, > Thanks for the reply. > I found this page, talking about simultaneous read/write to a single file > system. > > http://www.redhat.com/gfs/ > snap-------------------- > Red Hat GFS is commonly used in clusters of enterprise applications to > provide high speed access to a consistent file system image across the > server nodes. This allows the cluster nodes to simultaneously read and write > to a single shared filesystem. Typical application clusters where Red Hat > GFS is deployed today include: > -------------------------end of snap > > > Please can I have some technical idea, doc or flow chart type of thing > regarding GFS mechanism. > Thanks and Regards > Anuj Singh. > > On Wed, Apr 30, 2008 at 1:00 PM, Christine Caulfield <[EMAIL PROTECTED]> > wrote: > > > ???? Anuj Singh wrote: > > > Hi, > > > I have a question related to GFS + LVM and iscsi. > > > 1). I have a file test.txt on shared GFS file system, some user ramesh > > > opens test.txt to read, at the same time some other user Smith on the > > > network writes some data to test.txt file. > > > What data will Ramesh see in test.txt file which is changed after he > > > opened? > > > How does GFS handles data integrity? > > > > The same thing happens on GFS as would occur if you did that on a local > > file system. GFS does not provide any additional data integrity features > > over other file systems. If you can corrupt a file by writing to it from > > two places using ext3 on one node, then the same thing will happen using > > GFS, regardless of whether the processes are on the same or different > > nodes. > > > > The point of GFS is not to provide data integrity, but /metadata/ > > integerity. ie, the filesystem itself does not become corrupted by two > > nodes writing to the same inode or directory. > > > > So, the basic rule is: if it would corrupt data if two people on the > > same node did it on next3, then it will also corrupt data if two people > > on different nodes did it on GFS. > > > > I hope that's clear! > > -- > > > > Chrissie > > > >
