I’m starting a project to migrate our AFS cell from the ancient Solaris servers that it currently lives on to a number of RHEL VMs in our VMware infrastructure. One of the significant issues we’ve had for a long time is that performance is lousy on our current servers, and I’d like to make that better. I have a decent amount of flexibility in creating the VMs, and I’ve been reading around trying to figure out the best combination of system resources and server options for our AFS servers, and have not found a good, single document with specific recommendations. There’s a lot of stuff on various web pages, Wiki pages, and list postings going back over the last decade or so, but I was wondering if I could get some recommendations on the following items. Our cell is running OpenAFS 1.6.9, not heavily loaded, and we have only around 100 users and maybe 600-800GB of data spread across 3 file servers.
For DB and file servers, what is the recommended number of CPU cores and memory for each? I know at one point Jeff Altman mentioned that I actually wanted *fewer* cores, since there would be less cache missing across processors, but I assume I need more than one. I was thinking of having 2-core VMs created for the 3 DB servers and 3 or 4 file servers, with 2 or 4 GB (DB) and 8GB (FS) of memory for each. I’m not too worried about tuning the DB servers, but I know that tuning the fileservers is key. Right now we’re just using the -L and -nojumbo flags (I realize -nojumbo is deprecated), but it seems like tweaking the following options are recommended. Are these still the recommended values? -udpsize 128K or 256K (Yes, I know it has to be in bytes on the actual servers :) ) -sendsize 128K or 256K -vc ??? (Not sure what the best value for this is.) -cb 1.5M Finally, when I upgrade my DB servers, I know that the “right” way is to shut everything down, copy over the databases, and start up the DBs on the new hardware, but assuming everything is at OpenAFS 1.6.9, do you think I’d be safe to take down one database server at a time, bring up a new RHEL VM with the same IP address, start the AFS processes, and wait for the database to propagate to the new box? Sadly, while I know a lot about managing AFS, I have never dug as deep as I should have into the AFS internals. I was lazy and let Doug Engert deal with that stuff, but now he’s retired so it’s all up to me. :) Thanks! Brian -- Brian Sebby ([email protected]) | Infrastructure and Operation Services Phone: +1 630.252.9935 | Computing and Information Systems Fax: +1 630.252.4601 | Argonne National Laboratory
