I concur. I think it's the right time. On Wed, Feb 11, 2015 at 11:15 AM, Robbie Gemmell <[email protected]> wrote:
> This sounds reasonable enough to me. I dont think we really need a > formal vote on it though, its not a project release or procedural > issue, and whilst it is a behavioural change its not a major rework > (sounds like flipping a couple OFF/ON flags?) and isnt going to > require a much effort for anyone wanting the old behaviour. Putting it > out for discussion for a while as you have done seems sufficient to > me, and then proceeding if that discussion doesnt lead us in another > direction. > > Robbie > > On 10 February 2015 at 15:52, Kim van der Riet <[email protected]> > wrote: > > Since qpid began, what is now called legacystore has been the default > linux > > store for qpid builds. This is a per-queue circular disk buffer store. > This > > store has some management difficulties, the most egregious of which is > > managing the size of the disk buffer. It is easy for users to undersize > the > > buffer, and when it gets full, the store refuses to write further records > > until more space has been freed up. It is also easy for users to oversize > > all their queues so as to not run into this problem, and thus wastefully > > consume disk resources and massively increase the time necessary for > > recovery. > > > > Approximately a year ago work started on a new store called linearstore. > > This store is forked from legacystore, but the disk buffers are no longer > > fixed circular. Instead they are open-ended linear buffers, which take > their > > files from a common Empty File Pool. As new files are needed, they are > taken > > from the EFP and placed on the leading edge of the journal, while empty > > files are returned to the EFP from the trailing end of the journal. If > the > > EFP itself is emptied of files, the store will automatically create new > > ones. This removes the need for the user to guess at their worst-case > > scenarios to size a circular buffer. > > > > The linearstore also adds the ability to store the journals for > particular > > queues on different disk partitions. This allows some queues to use high > > performance media (such as solid state drives) where necessary, while > other > > queues can use regular disks. > > > > It is my belief that the linearstore has now progressed to the point > where > > it can now replace legacystore as the default store. Currently, both > stores > > are represented in the cmake build. However, linearstore defaults to OFF > > while legacystore defaults to ON. The reason for this is that both stores > > cannot be present at the same time or the broker will attempt to load > them > > both. Only one store at a time can be loaded in the broker, and having > both > > results in undefined behavior. I propose to leave legacystore in place > for > > the time being, but default the build to OFF, while linearstore will have > > its default set to ON. > > > > If you have any comments or concerns, please make them known. Otherwise > I'll > > start a vote on this in a few days. > > > > Kim > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [email protected] > > For additional commands, e-mail: [email protected] > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
