Date: Sat, 16 Sep 2023 23:01:42 +0000 From: bugzilla-noreply@freebsd.org To: fs@FreeBSD.org Subject: [Bug 267631] slow nfs from FreeBSD kvm guest/client to linux kvm host/server Message-ID: <bug-267631-3630-uctb1pjuXL@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-267631-3630@https.bugs.freebsd.org/bugzilla/> References: <bug-267631-3630@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D267631 Rick Macklem <rmacklem@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rmacklem@FreeBSD.org --- Comment #6 from Rick Macklem <rmacklem@FreeBSD.org> --- As you've noted, NFS performance issues are often network interface related. However, here are a few tunables you can try, beyond "readahead", which was already mentioned. (And, yes, the man page is out of date w.r.t. readahead. You can build a kernel from sources with the value bumped up from 16, but I doubt a value greater than 16 will be needed?) First, do this on the client when the mount is established: # nfsstat -m This will show you what it is actually using. You probably have NFSv3,TCP and an rsize of 64K or 128K. If you stick "vfs.maxbcachebuf=3D1048576" in the client's /boot/loader.conf, the rsize will probably go up to 1Mbyte. (It will also recommend that you increase kern.ipc.maxsockbuf and will suggest a value. I'd increase it to at least the recommended value.) A large rsize/wsize will have a similar effect to increasing readahead, but will affect writing as well as reading. nocto - Close to Open consistency will improve correctness when multiple clients access the same files. If your files are not being manipulated by multiple clients concurrently, turning it off can help. Most 10Gbps net interfaces use multiple queues and pin a TCP connection to a queue. As such, an NFS mount with a single TCP connection can only get a fraction of the bandwidth. nconnect=3DN can help here, but it only works for NFSv4.1/4.2, so you also need to specify the "nfsv4" or "vers=3D4" mount option. (No idea w.r.t. VMs.) Then there are all the cache timeouts "acdirmin,...". Similar to nocto, longer timeouts have a negative impact if other clients (or processes locally on the server) are changing things. But longer timeouts result in better caching. Then there is "noatime", since few care about the access time being up to date. However, nothing above will fix poor performance caused by a poor net interface. --=20 You are receiving this mail because: You are the assignee for the bug.=
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