8 Replies Latest reply on Oct 15, 2012 11:44 AM by Matt_Klein

    FileMaker Server 12 RAM Cache Flush

    Matt_Klein

      Hi All -

       

      I am just looking for some clarity on how the Cache Flush works in FileMaker Server 12 now that we cannot set the interval ourselves. I just had an incident where we lost a days worth of data because the server had to be restarted "ungracefully" so we lost everthing that was in the Cache.

       

      I presume that the cache is flushed when a scheduled backup is run. Please do correct me if I'm wrong.

       

      What else flushes the cache?

       

      Why do we no longer have the ability to set the interval? Is it because we have progressive backups now?

       

      I hadn't setup progressive backups on our server yet, shame on me. Needless to say it's done now.

       

       

      I'm just looking for a better understanding of how/when FMS12 writes the cache to disk. If this was a client it would have been far worse, so I'm trying to avoid the possibility with a client.

       

      Thanks in advance!

        • 1. Re: FileMaker Server 12 RAM Cache Flush
          wimdecorte

          The cache is flushed continiously.  That was the case in FMS11 and earlier too, the only difference there is that we could specify how long it would take to complete a full inspection of the cache.  So the old interval did not mean "flush the cache every x minutes".

           

          So it is hard to fathom how you would lose days worth of data... there were no backups running?  Or did they fail?  Any errors and warnings int he FMS or OS logs?

          1 of 1 people found this helpful
          • 2. Re: FileMaker Server 12 RAM Cache Flush
            Matt_Klein

            Hi Wim -

             

            Thanks for the reply.   I have never fully understood how the cache system works which explains why I thought the interval was a "flush the cache every x minutes" setting.    It does leave me confused though.   Can you explain how specifying a longer or shorter interval effects performance and resources on the server or could you point me to a discussion or paper on it.  I've done some searches and can't come up with anything.

             

            I digress.....This may not be a cache issue at all based on your reply.   Essentially what happened is we had to force the server to restart by hitting the power switch.  When it came back up, all data since the last backup was gone.   We had it setup to do a standard backup once a night.   I compared the last backup to the live files and they were identical as far as I could tell.

             

            Shame on me for not setting up progressive backups sooner.   Needless to say,  I did setup progressive backups after this event.  So,  we should have this problem again.

             

            Any ideas, if not cache, why we would lose all data since the last backup?   I automatically went to the RAM cache because it felt like all the data was stored in RAM and when we forced the restart the RAM obviously cleared without writing the data to the hard drive.

            • 3. Re: FileMaker Server 12 RAM Cache Flush
              wimdecorte

               

              Thanks for the reply.   I have never fully understood how the cache system works which explains why I thought the interval was a "flush the cache every x minutes" setting.    It does leave me confused though.   Can you explain how specifying a longer or shorter interval effects performance and resources on the server or could you point me to a discussion or paper on it.  I've done some searches and can't come up with anything.

               

              In FMS11 and earlier: say you have the cache flush set to 1 minute and you have the maximum of 800MB cache.  FMS will inspect 1/60 of that RAM every second, or 13.33MB to see if it contains any data changes that need to be committed to the hard disk.  The next second it inspects the next block of 13MB and so on until after the one minute it has inspected the full 800MB.

               

              In FMS12 the cache is inspected as a whole, and not in separate blocks so there is no need to specify an interval for it cycle through all the separate memory segments.

               

              Are there any clues in the underlying cause why you had to power off the machine?  Anything in the logs?

              Any other copies of the solution out there that the users may have used (on a network share somewhere) and where the data could have gone to?

              • 4. Re: FileMaker Server 12 RAM Cache Flush
                wsvp

                Hi Matt

                 

                Wondering if something prevented FMS from writing to the HD...

                ... Was it only FM data for that day? or all files on that drive for that day?

                ... Also could any system updates or virus protection have interfered with the normal operation of FM?

                ... Was the work lost, performed on multiple terminals or only one?

                 

                Another thing to consider... if a remote file could not connect to the preferred file reference due to a network problem... Could it have connected to an alternate/copy file reference somewhere else on the network or terminal?... And the days data wound up there.

                 

                I really hope FileMaker would never hold an entire days worth of data in RAM without writing it to the disk.  I was always under the "Assumption" (perhaps foolishly) that the data was written to disk upon commit.

                 

                You have probably checked these already, but figured I would chime in and say hi.

                 

                Mike

                • 5. Re: FileMaker Server 12 RAM Cache Flush
                  Matt_Klein

                  Nothing in the logs that I can see.   We were all working just fine and then suddenly we all lost connectivity to the FileMaker files.  I then tried to connect to the server via RDP to see what was going and it wouldn't allow connection.

                   

                  We do use that same server to do some development using Terminal Services, but we do NOT run any hosted files on it.

                   

                  It's almost impossible for a user to errantly open the wrong files.  I use a starter file that points to a specific hosted file which opens a local GUI file that is buried in a preferences directory by itself, aka no other FileMaker files with it.

                   

                  The only way it could have opened the wrong set of files would be if another complete set of the files was being hosted on the network.   The users don't have access to another copy of those files, so while I can't completely rule it out,  it is highly unlikely.

                  • 6. Re: FileMaker Server 12 RAM Cache Flush
                    Matt_Klein

                    Hi Mike -

                     

                    It appears to only be FM data for that day.  We don't store much data other than FM data on that server though we do use it for other things.   I don't have automatic updates or virus protection turned on.   I run both manually.

                    • 7. Re: FileMaker Server 12 RAM Cache Flush
                      LSNOVER

                      Hi Matt:

                       

                      Sorry to hear about your issues.  Do you have enough free disk space on your main OS drive?  Filemaker creates disk cache files as well, and they can get quite large.  It the primary hard drive gets full, it usually is not pretty with regards to Filemaker Server.

                       

                      Regards,

                      Lee Snover

                      • 8. Re: FileMaker Server 12 RAM Cache Flush
                        Matt_Klein

                        I currently have 15GB of free space on the OS partition.

                         

                         

                        BTW,  I don't believe that FileMaker Server caused the disconnect issue.    I was unable to get to the server with RDP at that time as well.   I was just surprised that a restart of the server resulted in data loss.   My immediate thought was RAM cache given that I abrubtly restarted the server with the power button.