On Mon, Oct 20, 2008 at 9:19 PM, Vikas Gorur <vikas at zresearch.com> wrote: > 2008/10/18 Stas Oskin <stas.oskin at gmail.com>: >> Hi. >> >> I'm evaluating GlusterFS for our DFS implementation, and wondered how it >> compares to KFS/CloudStore? >> >> These features here look especially nice >> (http://kosmosfs.sourceforge.net/features.html). Any idea what of them exist >> in GlusterFS as well? > > Stas, > > Here's how GlusterFS compares to KFS, feature by feature: > >> Incremental scalability: > > Currently adding new storage nodes requires a change in the config > file and restarting servers and clients. However, there is no need to > move/copy data or perform any other maintenance steps. "Hot add" > capability is planned for the 1.5 release. > >> Availability > > GlusterFS supports n-way data replication through the AFR translator. > >> Per file degree of replication > > GlusterFS used to have this feature, but it was dropped due to lack > of interest. It would not be too hard to bring it back. We moved this functionality to unify's switch scheduler from AFR, so glusterfs supports per file degree of replication - based on the file name. > >> Re-balancing > > The DHT and unify translators have extensive support for distributing > data across nodes. One can use unify schedulers to define file creation > policies such as: > > * ALU - Adaptively (based on disk space utilization, disk speed, etc.) > schedule file creation. > > * Round robin > > * Non uniform (NUFA) - prefer a local volume for file creation and use remote > ones only when there is no space on the local volume. > >> Data integrity > > GlusterFS arguably provides better data integrity since it runs over > an existing filesystem, and does not access disks at the block level. > Thus in the worst case (which shouldn't happen), even if GlusterFS > crashes, your data will still be readable with normal tools. > >> Rack-aware data placement > > None of our users have mentioned this need until now, thus GlusterFS > has no rack awareness. One could incorporate this intelligence into > our cluster translators (unify, afr, stripe) quite easily. > >> File writes and caching > > GlusterFS provides a POSIX-compliant filesystem interface. GlusterFS > has fine-tunable caching translators, such as read-ahead (to read ahead), > write-behind (to reduce write latency), and io-cache (caching file data). > >> Language support > > This is irrelevant to GlusterFS since it is mounted and accessed as a normal > filesystem, through FUSE. This means all your applications can run on GlusterFS > without any modifications. > >> Deploy scripts > > Users have found GlusterFS to be so simple to setup compared to other > cluster filesystems that there isn't really a need for deploy scripts. ;) > >> Local read optimization > > As mentioned earlier, if your data access patterns justify it (that > is, if users generally access local data and only occassionly want > remote data), you can configure 'unify' with the NUFA scheduler to achieve > this. > > In addition, I'd like to mention two particular strengths of GlusterFS. > > 1) GlusterFS has no notion of a 'meta-server'. I have not looked through > KFS' design in detail, but the mention of a 'meta-server' leads me to > believe that failure of the meta-server will take the entire cluster offline. > Please correct me if the impression is wrong. > > GlusterFS on the other hand has no single point of failure such as central > meta server. > > 2) GlusterFS 1.4 will have a web-based interface which will allow > you to start/stop GlusterFS, monitor logs and performance, and do > other admin activities. > > > Please contact us if you need further clarifications or details. > > Vikas Gorur > Engineer - Z Research > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://zresearch.com/cgi-bin/mailman/listinfo/gluster-users >
