Hi,

I recently had a power failure and on restarting, both my "Full Resolution Ocean" models crashed with "Error while computing".

Any advice on the best way to restore from a backup on a Mac?

David

I don't know Macs, but I seem to remember that their file structure is quite different to that of Windows, so I can't help with details.
Basically, all of the BOINC data section needs to be both saved and restored.

But...
If you're talking about a general full system backup, perhaps made by some regularly occurring process, then a restore may not be possible.

The problem here is that there is a Lockfile, which must be released by Exiting from BOINC before the save. Otherwise there'll be files missing from the "backup".

The most likely reason for the failures, is that there are a LOT of small files open when these models are running. All of these do get saved from time to time, but this takes a finite amount of time, and if the power failure occurred during the save, then some files on the HD will be current, and the others will be "from some time back". So there won't be a "full set" of files that can be used to restart the models after the power failure. Hence, CRAshhh.

---

Backups: Here

There's another problem, which is that copying away and pasting back does not generally work on Mac because of permissions changes. The usual solution would be to paste the backup back to the original location and then re-install BOINC Manager to re-establish the correct permissions. However, with CPDN applications this does not work. Indeed, it's worse than that: re-installing or upgrading BOINC Manager with an in-progress model will usually crash the model (thousands of models have been lost to this) ...

The new Australia and New Zealand HADAM3P model is the first application to be produced following the detailed diagnosis of the Mac permissions problem on the CPDN Beta site. I don't know whether the necessary fix has been applied to the new application. If so, then backups and, more importantly, upgrades should work.

[Edit: The Mac permissions fix has indeed been applied to the new ANZ application.]

Thanks for your replies.

I have a system backup done earlier whilst CPDN was suspended so presumably there wouldn't be any issues with a full restore? I'll give it try.

If you mean that the tasks and network activity were suspended within BOINC Manager, the restore may not work. Normally we say that you need to have fully exited from BOINC before making a backup. Perhaps that's what you mean.

Please let us know what happens.

---

Cpdn news

Ah, I did mean just a BOINC manager suspend!! Well, I'll try it anyway and see what happens.
In the absence of any activity, I had expected that a restore from an image backup would be problem free. We shall see.