Experimental Physics and
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On Fri, 2007-06-29 at 16:55 +0200, Thomas Birke wrote:When an ioc crashes, one of autosave's files can be corrupted, but it should not be possible to have both corrupted by a crash (or a reboot) during a file write. However, if the file server says a file is secure, and it's not actually secure (e.g., it hasn't actually been written to disk) then autosave can end up with both copies corrupted. If this is a possibility, one should specify that multiple copies of the save file be written. I don't know if files are the simplest and most reliable architecture, but if they don't work, lots of other things also don't work. * What are the disadvantages/advantages of ioc-based backup utilityOne advantage of an IOC-based autosave is that it can easily be made to start automatically whenever the IOC boots up. A disadvantage of this particular backup utility is that it overwrites the entire save file if any PV in the file has changed. At one point this was a generic limitation of least-common-denominator IOC software (vxWorks netDrv did not permit random access to a file). But now, since autosave requires NFS, it's just an annoying holdover that should be fixed. * Is there a SIMPLE way to generate a req/request file on the fly forThe list of PV's to be saved does not automatically configure itself to match PV's actually loaded. Autosave tolerates missing PV's, but if PV's come and go, their old values will not automatically be restored when they come back. Is it possible to generate a req file at ioc startup that save all theYes, but autosave doesn't provide much help. If you have a generic request file for each record type, listing the PV's that should be managed for that record type, you could use autosave's include-file capability to help with the job. Autosave doesn't kill itself if it can't find a PV. It's just a CA client, so its effect* What happens if the backup utility is looking for a record that doesn't exist? Is backup still ongoing? Does it significantly increase the traffic load on the network? on the network when PV's are not found is the same as any other CA client. Autosave doesn't log anything. It maintains only the most recent value.* Is log-on-change possible for individual output records? I heard this is not the forte of autosave, but I may be wrong. * What if there are no values previously saved on the particular ioc.If autosave has no value to restore, it will simply not restore, so the value in the database is used. I don't know whether casr and burt are still being maintained. Any client that* Although I am mostly interested in bumpless reboot, are there utilities that do bumpless reboot in a very similar way they do regular backup? I am currently using sddscasr (casr in sdds files ), but am reacquainting myself with casr and burt. Should I look at those or are they deprecated? Should I look at any other applications? can write a file can cause autosave to have that file restored at boot time. Autosave's save and restore operations are separately configured, so it can restore files that it did not save, and save files that it will not restore. * etc. -- Tim Mooney ([email protected]) (630)252-5417 Beamline Controls & Data Acquisition Group (www.aps.anl.gov/aod/bcda) Advanced Photon Source, Argonne National Lab
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ANJ, 10 Nov 2011 |
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