You hardware choice depends on the number of simultaneous clients the systems need to support. It also depends on the type of jobs / type of access (read only? many updates?).
Number and type of servers
Small system (up to 10 simultaneous jobs):
- One 4-CPU machine, such as Sun E420 acting as a data server, journal server, and lock server
Medium size system (10-50 simultaneous jobs):
- One 1-CPU machine acting as a lock server; no disk needed
- 1 CPU machine with small, but fast and reliable disk acting as a journal server
- One or two 4-CPU machine, such as Sun E420 acting as data servers
Large systems (over 50 simultaneous jobs):
- Lock server and journal server—as for a medium-sized system
- Number of data servers: a 4-CPU data server for every 30-40 jobs
Very large systems (over 200 simultaneous jobs):
- You might need to use multi-federation and bridge federation techniques, with one lock server per federation (or per every 150 jobs)
- Contact the SLAC database group for help
If you decide to put databases on more than one data server, you would need to setup placement, see Configuring placement.
At SLAC, we attach two large volumes (500-800 GB) to each 4-CPU data server. Maximizing the throughput usually requires monitoring the system and adjusting the configuration, depending on a bottleneck.
Here is an example of a real working configuration:
lock server - 1 CPU Sun Netra T1, 440 MHz, no disk required
journal server - 1 CPU Sun Netra T1, 440 MHz, 17 GB disk space (<1 GB would suffice)
data servers - 6 x Sun Ultra 80, 4 CPU, 450 MHz, 2 x 300 GB of disk space per server
This configuration is able to serve 220 clients (a client = 1 CPU Sun Netra T1, 440 MHz).
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Last Update: June 13, 2002