From 269da752908ac9a8ba0ab6d12e5e020cd3179657 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Sun, 27 Oct 2013 14:59:39 +0000 Subject: [PATCH] builder: Add a section on performance to the manual. (cherry picked from commit 2937c035958f84986e84c47df49f79d19c4b5b59) --- builder/virt-builder.pod | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/builder/virt-builder.pod b/builder/virt-builder.pod index c8e1ad7..bcd3615 100644 --- a/builder/virt-builder.pod +++ b/builder/virt-builder.pod @@ -1312,7 +1312,50 @@ etc are truly random when the guest boots. You should check digital signatures and not ignore any signing errors. -=head2 USER MODE LINUX +=head2 PERFORMANCE + +The most important aspect of getting good performance is caching. +Templates gets downloaded into the cache the first time they are used, +or if you use the I<--cache-all-templates> option. See L +above for further information. + +Packages required for the I<--install> option are downloaded using the +host network connection. Setting the C, C +and C environment variables to point to a local web cache +may ensure they only need to be downloaded once. You can also try +using a local package repository, although this can be complex to set +up and varies according to which Linux distro you are trying to +install. + +=head3 Skipping virt-resize + +Virt-builder can skip the virt-resize step under certain conditions. +This makes virt-builder much faster. The conditions are: + +=over 4 + +=item * + +the output must be a regular file (not a block device), B + +=item * + +the user did B use the I<--size> option, B + +=item * + +the output format is the same as the template format (usually raw). + +=back + +=head3 pxzcat + +Virt-builder can use C (parallel xzcat) if available to +uncompress the templates. The default is to use regular C +which is single-threaded. Currently this has to be compiled in, +ie. virt-builder will probably need to be recompiled to use pxzcat. + +=head3 User-Mode Linux You can use virt-builder with the User-Mode Linux (UML) backend. This may be faster when running virt-builder inside a virtual machine -- 1.8.4.2