Date: Tue, 16 Jan 2007 08:21:53 GMT From: Wolfgang Hurst<whurst@whurst.net> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/107975: NFS TCP read slow - write fast Message-ID: <200701160821.l0G8Lr4Q026941@www.freebsd.org> Resent-Message-ID: <200701160830.l0G8UKRa044673@freefall.freebsd.org>
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>Number: 107975 >Category: kern >Synopsis: NFS TCP read slow - write fast >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Jan 16 08:30:19 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Wolfgang Hurst >Release: FreeBSD 6.x >Organization: Tiscali >Environment: FreeBSD xxx.xxxx.xxx 6.2-STABLE FreeBSD 6.2-STABLE #3: Tue Jan 16 07:52:22 CET 2007 root@xxx.xxxxx.xxx:/usr/obj/usr/src/sys/XXXX i386 >Description: Server : s1 -> FreeBSD 6.2-STABLE (Intel) my private fileserver s2 -> FreeBSD 6.1-PRERELEASE (Dec 2006) customer fileserver Clients : c1 -> Solaris 8 (latest patches) my private client c2 -> Linux RE4 customer client I have problems with TCP NFS mounts. Read requests are very very very slow. On 100Mb/s network i have approx. 300 kb/s. On Gigabit ethernet i reach only 10 Mb/s. TCP write requests are fast with full speed of storage. on 100 Mb/s i have 90 Mb/s. On Gigabit network i have 150-200 Mb/s (storage speed) I saw this problem once and i fix this -> change to UDP. with UDP is anything fine. fullspeed in both directions. i googling but i found nothing about this problem. i think i'm the only one with this problem and i think -> the hardware sucks ... switching to UDP is fine -> forget it ... BUT yesterday a customer want tcp mount with an full difference freesbd and client. and he got the same problem. tcp ist slow on read but fast on write. on a full difference equickment. i have freebsd 5.x somewhere, on this server works anything fine. but since freebsd 6.x the nfs-tcp makes some problems. yes you can say .> mount via udp, but this is not possible, because udp mounts uses to many kernel memory and my private server rans out of memory. the kernel sad : "ENOMEM at bla" when he try to access the SATA devices. on linux the udp nfs crashes the host. it's uncool. i try to test many many sysctl values, but nothing helps. i think it's not a hardware problem, maybe the em (intel ethernet) device is broken. but rsync or other tcp services runns with full speed, it's only (nfs AND tcp AND freebsd6.x AND nfs-server) i know you have many other stuff to do, but somethink ist there very very strange. somewho should be look at this (maybe someone speak german :-))))) >How-To-Repeat: fresh install (server and client) export something on freebsd 6.x nfs server mount on client (solaris 8 or linux re4) transfer files >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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