Re: [Samba] excessive TCP retransmissions with samba 3.0, slow file opening RESOLVED
quote who=Jeremy Anderson Yeah, SMB is so blame chatty, and so impatient, that it just cacks on a hub. I'd never have believed it before, but when they can get a 24-port 10/100 DLink switch for $91 from newegg (shipped!), why mess around with technician time? At typical consultant bill rates, that switch will cost them less than an hour of technician time. Although a new switch did not fix my problem, it greatly improved performance (2x speed). A 90 second load time for my client's primary application is still not acceptable though. I have yet to load a network sniffer to see what else might be going on. The funny thing is, everything worked fine when the box was Redhat 7. When I upgraded to FC3 the issue started. I wonder what changed. So many possibilities. -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] excessive TCP retransmissions with samba 3.0, slow file opening RESOLVED
Jeremy Anderson wrote: Hello all! I've got a Fedora Core 3 box running Samba 3.0.8. It serves a variety of roles, including mail server and samba server. The mail server is quite fast, but the smb server generates lots and lots of TCP retransmissions (as seen in ethereal). The general consensus is that this is new in the last few weeks. One user has been reporting speed problems for some time, but no metrics were ever gathered. I've tried replacing the NIC, but the problem follows. This is a small network, with two 100mbit hubs, and windows 2000 on all the clients. I want to suspect hardware, but flood pings from a linux box put on the network never report dropped packets. All hosts are listed in DNS, and reverse DNS lookup is successful. I've also configured samba to pass WINS requests on to DNS. I'm absolutely stumped. I don't see the retransmissions with anything on the network except SMB-related TCP traffic. I don't see anything peculiar in /var/log/messages or the smbd.log file. nmbd is running just fine. Any assistance is greatly, greatly appreciated. I'd like to thank everyone for the help with this problem. Replacing the two Ethernet hubs with a single Ethernet switch seems to have resolved the problem. The two hubs were actually hot to the touch when I looked at them. I wouldn't have guessed that hardware would affect just a single protocol, but it looks like only SMB was chatty enough to overload the failing hubs. -- Jeremy Anderson jeremy (at) angelar.com http://www.angelar.com/~jeremy -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] excessive TCP retransmissions with samba 3.0, slow file opening RESOLVED
On Thursday 19 May 2005 20:53, Jeremy Anderson wrote: I'd like to thank everyone for the help with this problem. Replacing the two Ethernet hubs with a single Ethernet switch seems to have resolved the problem. The two hubs were actually hot to the touch when I looked at them. I wouldn't have guessed that hardware would affect just a single protocol, but it looks like only SMB was chatty enough to overload the failing hubs. I heard of a site that replaced the server because of performance problems caused by a $50 HUB. It is not as uncommon as you might think. The problem is that so few people will believe the story - and that means most will repeat the learning! Thanks for sharing the outcome with those of us who already believe. :-) - John T. -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] excessive TCP retransmissions with samba 3.0, slow file opening RESOLVED
- Original Message - From: John H Terpstra On Thursday 19 May 2005 20:53, Jeremy Anderson wrote: I'd like to thank everyone for the help with this problem. Replacing the two Ethernet hubs with a single Ethernet switch seems to have resolved the problem. The two hubs were actually hot to the touch when I looked at them. I wouldn't have guessed that hardware would affect just a single protocol, but it looks like only SMB was chatty enough to overload the failing hubs. I heard of a site that replaced the server because of performance problems caused by a $50 HUB. It is not as uncommon as you might think. The problem is that so few people will believe the story - and that means most will repeat the learning! Thanks for sharing the outcome with those of us who already believe. :-) I have followed this thread and believe I'm suffering from the same problem. File copying is terribly slow on one of my customers networks. The 8-port hub (which is plugged into a larger network switch) is a no-name piece of junk. However is worked fine when only network printers (jetdirects) was on it. Now that a windows XP box is on that hub, performance went down hill and I even get errors in the syslog about failed smb gethostnames or something like that. -Eric Wood -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] excessive TCP retransmissions with samba 3.0, slow file opening RESOLVED
Eric Wood wrote: I have followed this thread and believe I'm suffering from the same problem. File copying is terribly slow on one of my customers networks. The 8-port hub (which is plugged into a larger network switch) is a no-name piece of junk. However is worked fine when only network printers (jetdirects) was on it. Now that a windows XP box is on that hub, performance went down hill and I even get errors in the syslog about failed smb gethostnames or something like that. -Eric Wood Yeah, SMB is so blame chatty, and so impatient, that it just cacks on a hub. I'd never have believed it before, but when they can get a 24-port 10/100 DLink switch for $91 from newegg (shipped!), why mess around with technician time? At typical consultant bill rates, that switch will cost them less than an hour of technician time. I bet if you fire up ethereal on that hub, you'll see plenty of TCP retransmits... -- Jeremy Anderson jeremy (at) angelar.com http://www.angelar.com/~jeremy -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
