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Hi Derek, Derek Feichtinger wrote: > Hi, > > This is slightly off-topic, but nontheless important for the setup of large > direct attached storage systems typically used with xrootd. Maybe some of you > have good suggestions or experiences. > Well, I don't know exactly your requirements, but wouldn't it be sufficient to look at the traffic by making an average of the data seen by each client after the file close ? Another (better) way could be to setup XrdMon. Why not ? Fabrizio > For our next upgrade of our Tier2 I would need a benchmark with which I can > measure whether I can satisfy an I/O requirement per worker node (WN, or CPU > core). This has to be tested while all WNs are reading in parallel from all > file servers. I just want to assume that the clients from the WNs are reading > in a nicely distributed fashion from the file servers, e.g. in the case of 10 > file servers and 150 WNs, I would assume that in average 15 WNs are reading > at the same time from any file server. But any combination of 15 WNs must be > able to yield the desired bandwidth. > > Naturally, this benchmark is targeted at mimicking a cluster running analysis > applications. > > A primitive test (but not exactly matching the use case) could be using > netperf or iperf in UDP mode. E.g. the file servers would receive packets > from the required fraction of worker nodes (The sending intervals and packet > sizes can be set for netperf). One would gradually increase the sending rate > per worker node until UDP packet loss is observed. > > I'm glad for any suggestions. > > Cheers, > Derek >