Moving to HRD is the safest way to ensure that your users are not impacted during a downtime. Memcache and other mechanisms can be used, but will definitely not scale and aren't guaranteed to be resilient in the face of all downtime scenarios.
For the particular issues reported on this thread, we have a few root causes that we're looking into. In terms of a fix though, all of the affected apps are running on M/S and, as a result, our options are much more constrained -- we're not able to move the as apps freely as we can with HRD-based applications. M/S worked really well when it was first rolled out, but given the increase in number of apps and datastore transactions we needed an even better solution -- thus HRD. While the pros and cons of HRD have been discussed and debated within this group, the simple fact is: if you want to minimize your exposure to downtimes you need to move over to HRD. There's an SLA of 99.95%, which we've consistently beat<http://googleappengine.blogspot.com/2012/01/happy-birthday-high-replication.html>month over month. We're committed to resolving the current issue, but I strongly urge anyone running on M/S to make the move over to HRD. It's the quickest and most long-term fix that you can make. -- Chris Ramsdale Product Manager, Google App Engine On Mon, Mar 12, 2012 at 2:33 PM, Amit Sangani <[email protected]>wrote: > Hi Ikan, > > We wouldn't mind moving to HRD from M/S, but isn't it 3X more expensive? > > Also, what's the minimal way to impact our users when datastore is in > read-only mode during downtimes? Consider that every action our users take > involves writing to a datastore. Will using memcache help? Will memcache be > available without interruption during datastore downtime? > > thanks! > Amit > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/google-appengine/-/MooASjwFQ28J. > > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
