On Wed, 2006-07-05 at 14:30 +1000, RR wrote: > Hi Wendy, > > thanks for the prompt response. I see what you're saying. Just a few > things to clarify. The databases I have are clustered active-passive, > so only one machine accesses the store at any given time with a > persistent connection to the SAN. > Also, yes, I would think that for this particular application the IO > pattern might be very close to parallel in nature as essentially all > cluster nodes will run the same application accessing the same store > but may rarely access the same folder at the same time and if they do, > it would be independantly of each other. I guess the community > involved with the development of this application isn't too familiar > with clustered filesystems and they may be considering database > storage over shared filesystems such as NFS or something but they seem > to suggest that database storage offers better scalability and less > administrative overhead. I do care about the administrative overhead > but performance is a bigger criteria. The other thing I should point > out is that whereas the clustered databases use HBAs to access the SAN > the linux cluster nodes running the application will access the SAN > using GigE NICs. The performance and CPU overhead of not being able to > use HBAs might be an added factor, do you think? Why do you think cluster nodes accessing SAN using GigE NICs ? It is a mis-understanding. GFS accesses its storage via (fibre channel based) HBAs unless you configure the system using GNBD or ISCSI). > > I'm totally neutral about either solution, I just want the best > performance with whatever I go with, so I wonder if a database person > on the list can give their view as well? > Again, you *need* to benchmark your workload before making any decision. We're certainly working hard to improve GFS but it is not a cure-all solutions. Same sentence - workload dependent and test your configuration before locking into anything ... -- Wendy -- Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
