On 19 Nov 2012, at 07:15, Jakub Moscicki wrote: > Thanks for this analysis. The increased UDP works pretty well for us at CERN > so far - albeit one limit gone other limits appear more pronounced.
I'm interested in what other limits you are hitting. I'm very aware of the problems with the listener thread load and scheduling, are you hitting any other problems with RX, or are they fileserver limitations? >> management packets. 16Mbytes should be plenty providing that you don't >> >> d) Have a large number of 1.6.0 clients on your network > > Do you mean 1.6.0 (referring to a specific bug in 1.6.0) or 1.6.x (referring > to some general change in client behaviour in 1.6 series)? Specificaly 1.6.0, and prereleases. There is a truly unfortunate bug in those clients which causes them to create a gradually escalating ping flood against every fileserver they contact. At its worst, this creates a distributed denial of service attack against your fileservers. In terms of this discussion, the large number of incoming RX version packets can overwhelm the listener thread. As these packets are not flow controlled, they can force "real" data packets out of the UDP buffer. One solution to this problem is to drop these packets at the kernel firewall - you want to drop all version packets with an RX epoch of 999. Cheers, Simon_______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
