Eric, I believe your first example is intended to describe an existing Fedora repository (you mentioned running 3.4 previously) that you're upgrading to 3.6.2 while continuing to use the legacy llstore. I just want to emphasize that for anyone who hasn't been following the thread, as I would strongly dissuade someone bringing up a new Fedora repository to select the legacy llstore.
There's nothing to transfer/migrate in the case of external datastreams: an external datastream is just a pointer to a location that the repository has no responsibility over. Migrating managed datastream content from a legacy llstore to the default Akubra filesystem store is quite straightforward, but potentially time-consuming (e.g. depending on the same filesystem, vs across filesystems, amount of data, etc.). Chris Wilper built a utility (described here: https://wiki.duraspace.org/display/~cwilper/A+New+Fedora+Storage+Utility) that can be used precisely for tasks such as migrating from llstore to akubra. Akubra is pretty flexible. It's designed to let you implement your own datastore and mapping modules and to multiplex different storage backends too. So in theory, I think yes, you could implement your own Akubra modules that would let you access both legacy and hash-based stores at the same time, but I doubt that the overall calculus would make that effort worthwhile versus a one-time migration. There aren't any foxml or database consistency issues in a storage migration (other than actual concerns at the operating system or hardware level of losing or flipping bits as part of copying files). As for migrating to Fedora 4, it's a bit early yet for me to be able to predict the level of effort required to upgrade. That said, every stakeholder funding and putting developer resources into Fedora 4 is a Fedora 3 institution and so there is no question that there is a strong commitment to, and strong degree of self-interest in, a solid migration path. Moreover, for the ten+ year history of the project, we have always provided migration support to new versions. This isn't about to change. If anything, given the performance and scalability improvements slated for Fedora 4, I would expect the migration to be far faster and smoother than we've been able to support previously. -Eddie On Mar 15, 2013, at 11:00 PM, "James, Eric" <[email protected]> wrote: > Thanks to everyone in the discussion a few days ago about the Managed content > and lowlevel storage, I found people's comments really helpful. Of course > this just brings more questions that again I ask to this list - regarding the > long term viability of current fedora usage. > > For example, say we deploy a fedora 3.6.2 today and ingest a few TBs of > Managed content using the fedora legacy low level store, but in a year from > now wish to migrate to an akubra/iRODS back end. Does fedora have > functionality to facilitate a migration such as this? How would you go about > transferring the /fedora/data/ from one filesystem to another while > maintaining the consistency of the fedora database and its foxml? Would the > answer to this question differ for Managed or External datastreams? Or could > you have one instance of fedora that accesses both a legacy store and new > store at the same time? And for fedora itself, when version 4 rolls out, > what level of effort will there be in upgrading fedora 3.x to it? > > Thanks, > Eric > > ________________________________________ > From: [email protected] [[email protected]] > Sent: Wednesday, March 06, 2013 6:51 PM > To: Support and info exchange list for Fedora users. > Subject: Re: [fcrepo-user] LLStorage > > Part of the impetus of the Akubra development was to support many different > kinds of disposition for content across persistence services. I can't speak > to the efforts around particular vendor-specific solutions, but as a > homegrown example I can point at: > > http://uvalib.github.com/twostore/ > > which is what we are currently using here at UVa. It may provide some ideas > about how to use Akubra to create some flexibility and scalability in your > persistence. > > --- > A. Soroka > The University of Virginia Library > > On Mar 6, 2013, at 3:41 PM, Randy Fischer wrote: > >> I'd love to hear how other people are doing this, or opinions on the above >> plan. > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_mar _______________________________________________ Fedora-commons-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/fedora-commons-users
