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hosts/common/fs: optimize NFS options

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Colin 2024-03-28 18:47:22 +00:00
parent eadb2057d9
commit 701e10b121
1 changed files with 19 additions and 5 deletions
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24
hosts/common/fs.nix
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@ -23,7 +23,8 @@ let
# N.B.: `remote-fs.target` is a dependency of multi-user.target, itself of graphical.target.
# hence, omitting `noauto` can slow down boots.
noauto = [ "noauto" ];
# lazyMount: defer mounting until first access from userspace
# lazyMount: defer mounting until first access from userspace.
# see: `man systemd.automount`, `man automount`, `man autofs`
lazyMount = noauto ++ automount;
wg = [
"x-systemd.requires=wireguard-wg-home.service"
@ -67,18 +68,31 @@ let
# actimeo=n = how long (in seconds) to cache file/dir attributes (default: 3-60s)
# bg = retry failed mounts in the background
# retry=n = for how many minutes `mount` will retry NFS mount operation
# intr = allow Ctrl+C to abort I/O (it will error with `EINTR`)
# soft = on "major timeout", report I/O error to userspace
# softreval = on "major timeout", service the request using known-stale cache results instead of erroring -- if such cache data exists
# retrans=n = how many times to retry a NFS request before giving userspace a "server not responding" error (default: 3)
# timeo=n = number of *deciseconds* to wait for a response before retrying it (default: 600)
# note: client uses a linear backup, so the second request will have double this timeout, then triple, etc.
# proto=udp = encapsulate protocol ops inside UDP packets instead of a TCP session.
# requires `nfsvers=3` and a kernel compiled with `NFS_DISABLE_UDP_SUPPORT=n`.
# UDP might be preferable to TCP because the latter is liable to hang for ~100s (kernel TCP timeout) after a link drop.
# however, even UDP has issues with `umount` hanging.
#
# N.B.: don't change these without first testing the behavior of sandboxed apps on a flaky network.
nfs = common ++ [
# "actimeo=10"
"bg"
"retrans=4"
# "actimeo=5"
# "bg"
"retrans=1"
"retry=0"
# "intr"
"soft"
"timeo=15"
"softreval"
"timeo=30"
"nofail" # don't fail remote-fs.target when this mount fails (not an option for sshfs else would be common)
# "proto=udp" # default kernel config doesn't support NFS over UDP: <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1964093> (see comment 11).
# "nfsvers=3" # NFSv4+ doesn't support UDP at *all*. it's ok to omit nfsvers -- server + client will negotiate v3 based on udp requirement. but omitting causes confusing mount errors when the server is *offline*, because the client defaults to v4 and thinks the udp option is a config error.
# "x-systemd.idle-timeout=10" # auto-unmount after this much inactivity
];
};
remoteHome = host: {