William Schumann wrote: > Elaborating upon zfs and zpool enhancements to AI. BE considerations - > add name of BE to create. > > As always, feedback is desired. Also opinions as to the value of these > features - how useful are they? > > The concept of overwriting existing pools was reconsidered. The > question here is what to do with a pool if it has <zpool_create> and it > already exists. "Overwrite" is a misnomer and will not be used here. > > There are a few different pool reuse cases: > 1) the user wants to reuse the manifest and preserve the pool the > created with the manifest > 2) the user wants to remove contents from the pool and reuse it without > having to know its options or vdevs > 3) the user wants to redefine the pool, changing options or vdevs > > For the first option, adding boolean attribute "preserve" will result in > any associated manifest definitions of vdevs, mirrors, and options being > ignored, and the zpool will be unchanged, except for BEs in the root > pool (discussed below) > > For the second, adding boolean attribute "destroy_all_datasets" will > cause any datasets to be destroyed, including any BEs > > For the third, the user must <zpool_destroy>, then <zpool_create> > according to the new specifications. > > For root pools, the preserve options become more interesting. If the > root pool exists, it could contain BEs that the user may want to > preserve. Propose for the zfs_root_pool section, add BE_name element. > If named BE does not exist, just install OpenSolaris into that BE. If > it does exist, fail the install unless boolean attribute > destroy_be_if_it_exists is true in which case the BE is first deleted, > then recreated. When a BE is not named, take the default behavior, > which is to use 'opensolaris' BE, destroying it if it exists. > > My original draft of the AI manifest schema allowed the user to create a > filesystem in the context of a zpool: > <ai_manifest name="default"> > ... > <ai_zfs_pool> > <zpool_create name="zoolpool"> > <vdev>c0t0d0</vdev> > <zfs_fs_create path="mynewzfs"/> </zpool_create> > </ai_zfs_pool> > > would result in: > zpool create zoolpool /dev/dsk/c0t0d0 > zfs create zpoolpool/mynewzfs > > Added the ability to create a zfs file system without the pool context, > at the top XML level: > <ai_manifest name="default"> > ... > <zfs_fs_create path="poolname/fully_specified_path"/> > would result in: > zpool create poolname/fully_specified_path > > Also added to the manifest the ability to create a zfs filesystem as a > child of another zfs filesystem. > <zfs_fs_create path="mynewzfs"> > <zfs_fs_create path="child_of_mynewzfs"/> </zfs_fs_create> > <!-- end mynewzfs --> >
What do these variants buy us? Why would I use them vs. the other form? Dave
