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Hi, We should add these recommendation to OSG Release Documentation. Patrick, if the increasing the number opened files will not help and if the "CLOSE_WAIT" problem has been solved for xrootd 20100315-1007 release, you can probably upgrade xrootd from ITB cache. Thanks, Tanya -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] On Behalf Of Andrew Hanushevsky Sent: Monday, April 12, 2010 4:58 PM To: Patrick McGuigan; [log in to unmask] Cc: [log in to unmask] Subject: Re: Overloaded Xrootd dataserver? Hi Patrick, Please tell me the release you are running. We did put in a CLOSE_WAIT fix recently. That aside, we always recommed setting the FD limit to as high as practical for your OS (at least 8K and preferably 16K to 32K). 1K is not recommended and will likely lead to problems regardless of any extant bugs. Andy ----- Original Message ----- From: "Patrick McGuigan" <[log in to unmask]> To: <[log in to unmask]> Cc: <[log in to unmask]> Sent: Monday, April 12, 2010 2:08 PM Subject: Overloaded Xrootd dataserver? > Hi, > > I am having an issue with one of our data servers and it may be getting > overloaded with requests from clients. > > The symptoms are that the load on the SRM machine will get very large > because threads there are talking through XrootdFS for various connections > to the dataserver. Various activities related to Xrootd will fail (SRM > get's hung, gridftp servers won't send data). > > When logged into the dataserver and running strace on the xrootd service I > see that it has a problem in accept() because of too many open files. > > If I do a netstat I see that xrootd is holding a large number of sockets > in a CLOSE_WAIT state. > > I am trying to understand if the problems that I am seeing are because the > limits (1024 open FD's) given to xrootd are too small or if the problem > with xrootd is that the service is too overloaded and this is causing > xrootd to hang on to too many sockets. > > Regards, > > Patrick >