Re: [Libguestfs] [PATCH virt-v2v] v2v: Allow temporary directory to be set on a global basis.

On Tuesday, 7 April 2020 14:18:47 CEST Richard W.M. Jones wrote: > On Tue, Apr 07, 2020 at 01:25:02PM +0200, Pino Toscano wrote: > > The important thing is still that that you need to have space for the > > temporary files somewhere: be it /var/tmp, /mnt/scratch, whatever. > > Because of this, and the fact that usually containers are created > > fresh, the cache of the supermin appliance starts to make little sense, > > and then a very simple solution is to point libguestfs to that extra > > space: > > > > $ dir=$(mktemp --tmpdir -d /path/to/big/temporary/space/libguestfs.XXXXXX) > > $ export LIBGUESTGS_CACHEDIR=$dir > > $ export TMPDIR=$dir # optionally > > $ libguestfs-test-tool > > [etc] > > $ rm -rf $dir > > > > Easy to use, already doable, solves all the issues. > > So AIUI there are a few problems with this (although I'm still > investigating and trying to make a local reproducer): > > - The external large space may be on NFS, with the usual problems > there like root_squash, no SELinux labels, slowness. This means > it's not suitable for the appliance, but might nevertheless be > suitable for overlay files. If that is the only big storage space attached to a container, I do not see any alternative than use it, with all the caveats associated. Also, if we take as possible scenario the situation where /var/tmp is not that big, then we need to consider that may not be big enough to even store the cached supermin appliance (which is more than 300/350MB).