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Use overlayfs instead of unionfs-fuse in the VM tests

Overlayfs is quite a bit faster, e.g. with it the KDE 5 test takes ~7m
instead of ~30m on my laptop (which is still not great, since plain
9pfs is ~4m30s).
This commit is contained in:
Eelco Dolstra 2016-12-21 20:49:08 +01:00
parent 9e6ac83f2a
commit ea46420fc0
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@ -278,7 +278,7 @@ in
description =
''
If enabled, the Nix store in the VM is made writable by
layering a unionfs-fuse/tmpfs filesystem on top of the host's Nix
layering an overlay filesystem on top of the host's Nix
store.
'';
};
@ -395,6 +395,13 @@ in
chmod 1777 $targetRoot/tmp
mkdir -p $targetRoot/boot
${optionalString cfg.writableStore ''
echo "mounting overlay filesystem on /nix/store..."
mkdir -p 0755 $targetRoot/nix/.rw-store/store $targetRoot/nix/.rw-store/work $targetRoot/nix/store
mount -t overlay overlay $targetRoot/nix/store \
-o lowerdir=$targetRoot/nix/.ro-store,upperdir=$targetRoot/nix/.rw-store/store,workdir=$targetRoot/nix/.rw-store/work || fail
''}
'';
# After booting, register the closure of the paths in
@ -412,7 +419,8 @@ in
'';
boot.initrd.availableKernelModules =
optional (cfg.qemu.diskInterface == "scsi") "sym53c8xx";
optional cfg.writableStore "overlay"
++ optional (cfg.qemu.diskInterface == "scsi") "sym53c8xx";
virtualisation.bootDevice =
mkDefault (if cfg.qemu.diskInterface == "scsi" then "/dev/sda" else "/dev/vda");
@ -447,12 +455,6 @@ in
options = [ "trans=virtio" "version=9p2000.L" ];
neededForBoot = true;
};
} // optionalAttrs cfg.writableStore
{ "/nix/store" =
{ fsType = "unionfs-fuse";
device = "unionfs";
options = [ "allow_other" "cow" "nonempty" "chroot=/mnt-root" "max_files=32768" "hide_meta_files" "dirs=/nix/.rw-store=rw:/nix/.ro-store=ro" ];
};
} // optionalAttrs (cfg.writableStore && cfg.writableStoreUseTmpfs)
{ "/nix/.rw-store" =
{ fsType = "tmpfs";